Modification Physics SPM

CHAPTER 1
1. Suitable ruler to use in laboratory
Suggestion Explanation
Smallest size scale 0.1 cm More accurate
High accuracy Less error in measurement
High consistency Low relative deviations
Plastic material Avoid parallax error
Thin thickness Avoid parallax error
CHAPTER 2
2. Explain the suitability feature of arm exercise equipment.
Spring made of steel Can withstand higher force
Two // more spring arrange in parallel The spring system is stiffer
Spring with ticker wire Wire will not easily break
Smaller diameter coil of spring The smaller the diameter coil less elastic the
spring, so the arm exercise would not so hard
Choose large force constant spring Will make strong spring, the spring will stiffer and
not broken easily
3. Suggest the suitable cloth , equipment and techniques to improve high jumper athlete and
their safety .
4. Explain the characteristic of spring to make baby’s cradle.
Choose large force constant spring Will make strong spring, the spring will stiffer and
not broken easily.
Choose large diameter of wire The larger diameter the stiffer the spring is.
Large diameter coil of spring The larger the diameter coil more elastic the spring
is
The spring is made of steel or alloy Steel and alloy is stiffer than iron
The arrangement of spring is two or
more line in parallel
The spring is stiffer
5. Explain the most suitable design of spring for shock absorber for motorcycles.
Small diameter of spring coil Enough space for the spring
Choose large diameter of wire The larger the diameter the stiffer the spring
Force constant is more than 1000N Can support motorcyclist and passenger up to
100kg
Higher spring constant Small compression of the spring
Small natural frequency To reduce bumping, comfortable for user
6. Explain the simple characteristic of the rocket than can travel with greater acceleration.
Suggestions Explanations
Choose metal with high strength and
hardness
Even under pressure the shape will not change
easily
Frame of rocket is made of low density Lighter, can increase acceleration
suggestion Explanation
Use tight and light suit Less air fraction
Use spikes shoes Better grip support while running and prevent
slippery
Use thicker mattress Increase time impact , reduce impulsive force .
prevent back injury
The athlete have to sprint before jump Can increase kinetic energy
Athlete have to bend the body during
fall
Increase the time impact , reduce impulsive force

metal
Multistage rocket invented Each stage has burning fuel, pump and combustion
chamber. It will slip off when fuel of each chamber
completely burn. When the mass decreases, the
acceleration increase
Rocket need to carry a tank of oxygen To enable the combustion of fuel in space
Silver color rocket Reflect light efficiently so the temperature of the
rocket will not rise
Cover the body of rocket with heat
insulator
Friction between air and body will increase heat.
The insulator will reduce heat conductivity
Aerodynamic shape Reduce air friction, move faster
7. Suggest and explain the build of water bottle rocket in school competition to move higher
altitude and has longer time on the air.
The body of rocket must be tough Do not break easily in high pressure and when
landing
Smaller mass Rocket will accelerate faster
The shape is streamline/aerodynamic Reduce air resistance
Nose cone or bullet shape on top of
body
To improve the aerodynamic of rocket
45 angle of launching The rocket can travel maximum distance
The volume of water is half or 1/3 from
the whole volume
To increase momentum and impulsive force
Attach 3 or 4 fins at the tail of rocket
space equally
Rocket will move smooth and stable
Attach parachute will make the rocket floating and has longer time
on the air before landing//decrease the speed of
falling due to air resistance
8. Give suggestion to improve the design of jet engine so that it can be use for larger airplane at
the higher speed.
Increase more fuel injectors More fuel to be burnt to produce greater force
Increase the size of the combustion
chamber
More space for fuel to burnt
Decrease the diameter of the nozzle Exhaust gas ejected at higher velocity
Increase the speed of blade/use bigger
blade
Increase the air intake
Blade and engine made of strong
materials
Can withstand strong pressure and won’t break
easily
9. Base on the physic principle, suggest the design of roller skate track so it can be use to
oscillate skate continuously.
Semi circular curve shape Exchange between kinetic energy and gravitational
potential easily
Smooth surface Reduce frictional force/easy to slide
The slope slightly increase and
decrease
Easy to oscillates cause by changing of energy
Use strong material such concrete of
foundation of the track
Withstand high impact such as high force of
jumping and landing
Soft layer at the surface Reduce impulsive force when landing, low risk if
accident
10. Explain the most suitable design of motorcycle that can move fast, safe and save time in
racing.
Lower seat height Lower center of gravity or more stable or safer to
turn.
Bigger width of tire Bigger surface area, better support or low pressure

acts on the tires or more friction when breaks.
Less thread pattern To decrease friction of tires to the road, can move
fast
Smaller mass Lighter, can move faster or low inertia
With ABS Motorcycle does not stop immediately or can be
controlled if direction changes or does not move
sideways or more friction with ABS
11. Suggest and explain how to make suitable beach motorcycle which able to move on the sand
smoothly and comfortable.
Deep thread patter // more definitive
pattern
Better grip on sand, able to move smoothly on
sand
Large tire (big surface contact with
ground)
Reduce total pressure of car, increase stability and
the car would not get stuck in the sand
Soft seat and water resistance Comfortable for cycles and would not get wet
easily
Excellent resistance to rusting Everlasting. Would not rust easily
Attach shock absorber with higher
spring constant and small natural
frequency.
Reduce bumping, comfortable to cycle with
Low density body Lighter, would not stuck in sand
12. Suggest the suitable cloth and the best techniques to catch ball to prevent injury for
goalkeeper.
Suggestion Explanations
Wear glove Reduce painful of the player’s hands when
touching the ball with big impulsive force.
Use soft material for glove Lengthen the time impact, reduce impulsive force.
Wear cloth which is made from material
with moderate specific heat capacity
The cloth can absorb more heat when the player is
sweating to maintain the temperature of player.
Base of shoes has stud Player give great pressure to make stud sink into
ground and give stronger support without slipping.
When catching the ball, the goal keeper
should move his hand backwards
This action lengthen the time impact between ball
and hand, so it reduce the impulsive force.
The ball should have enough air
pressure inside
Shorter the time impact between foot and ball, so
impulsive force increase then the ball will has high
speed and travel far away.
13. Using physics concept, suggest and explain suitable athlete’s attires, running, jumping, landing
techniques and other aspects to help the long jumper can jump further.
Use tight and light suit Less air friction
Use spike shoes Better grip support while running and prevent
slippery
The athlete have to sprint before jump Can increase the kinetic energy//momentum
The athlete have to push the body
infront while jumping
Increase the elastic potential energy//able to
increase longer distance of jumping
Athlete have to bent the body during
fall
Increase the time impact, reduce impulsive force,
less injured
14. Safety feature in car
Characteristic Explanation
The bumper of car is prone to crash It will increase the time impact, the impulsive force
will reduce
The sitting space of the passenger is
reinforced
To protect the passenger
Use safety belt During collision, safety belt will hold the
passengers from thrown infront due to inertia
Use air bag Will inflate when accident occurs, the driver safe
from hitting steering
Antilock breaking system(ABS) Allow car to stop quickly on slippery road and

prevent from skidding
Strong steel struts Give good protection from side on collision
Tire with tread Can stays contact with road, prever slippery
15. Explain the suitable loaded lorry which can carry liquid, such as petrol
The load of lorry should be divided into
many smaller tank
To reduce effect of inertia
The load must be tied So it will no fall of from the lorry
Far gap distances between tractor and
trailer
Prevent collision between tractor and trailer, easier
when turning
Use more tire for lorry Pressure will be separate to all tires, able to carry
more loads. Lower pressure better support and
stability
Small belt behind lorry To discharge spark, safety reason to prevent from
burning the petrol
Use antilock break system (ABS) The lorry can stop easily without skidding
16. Explain the design of and how kayak which can travel faster and safer.
Streamline /aerodynamic shape of body Reduce water resistance
Smooth surface body /coated with wax Reduce friction of body towards water
Low density material Lighter , easier to float, easy to carry and sail
faster
Strong material body and peddle Everlasting , not easily broken
Wider peddle surface Greater force because more water are peddled up
Wear safety jacket Passenger can float and safe if they fall into water.
17. Give suggestion to design a sail boat which can travel faster and smooth.
Streamline /aerodynamic shape of
board
Reduce water and air resistance,can increase
lifting
Smooth surface board/coated with wax Reduce friction toward water
Low density material Lighter, easier to float and sail faster
Strong material Withstand strong wind, not easily damage
Wider sail Greater lifting force because more wind are
captured
18. Modified the ship that can carry more and heavier load, move faster and safe while travelling.
Strong material Can withstand great force
Low density material Light weight
Has more than two stage,plimsoll line Safe to travel on the fresh and salt water
Big size Can place more goods
Aerodynamic/streamline shape Reduce water friction.
Waterproof sail Sail would not get e=wet easily.
19. Suggest how to increase the safety for motorbike racer to reduce injuries / accident
20.
A
n earth-monitoring satellite falls into the earth’s atmosphere at a high velocity and reaches a
high temperature. This is caused by the earth’s gravitational force and air resistance.Using the
appropriate physics concepts, suggest and explain suitable designs or ways to protect the
satellite and its equipment:
Use helmet To protect the head
Use helmet with hard outer casing and
soft inner liner
Helmet reduce head injuries in a crash by
spreading the impact with hard outer casing and
absorb energy with soft inner linear of styrofoam
Use safety jacket To protect the from injuries , cut ,burn
Use gloves To protect the hand
Use padded leathers suit Will soften any impact and protect the skin from
abrasion

Aerodynamic shape To reduce air resistance
Heat shield / material that is hard to
burn
To protect the capsule
High melting point //ceramic Do not melt
Landing in water // air bag Increase time of impact// Reduce impulsive force
Light material / / small mass // low
density
-Reduce the inertia // -reduce the momentum //
-reduce impuls
Paracute / /Retro rocket To reduce speed
Hard material // stiff composite Not easy to bend
21. Explain how you would design the pile driving system.[the ram hammer is lifted to a height by
the crane and allowed to fall on the pile.
Modification Reason
Large hammer weight Large momentum when it hit the pile
Ram hammer made from hard material
such as alloys
Not break easily/last longer
Hammer raised at higher position Inrease the gravitational potential energy
Stronger End of the top of the concrete
pile
To avoid break at the top couse by the hammer
Sharp End of the bottom of the
concrete pile
To increase the pressure
CHAPTER 3
22. Efficient brake system
Type of liquid: oil Uncompressible
Thickness of brake line :high To counter the high pressure from the liquid
The ratio of cross sectional area for
wheel piston and master piston :high
To produce larger force on wheel piston
The chosen of type of brake for front
rear wheel:
Front wheel - disc
Rear wheel - drum
Disc brake is more efficient than drum brake
23. Explain the design of hydrometer which can be use to determine a wide range of densities of
liquid.
Small stem and long Increase sensitivity where the scale division are far
apart so that small changes in density can be
detected
Glass wall Do not erode and small adhesive force
Large diameter of bulb High up thrust / displaces more liquid / able to float
easily
Scale can be made bigger or smaller
than the density of water.[calibration]
- The hydrometer is floated in
alcohol. The liquid level at the
stem is marked (upper level)
- Then, the hydrometer is floated
in higher density liquid like
mercury and marked (lower
level)
Ability to measure a wide range of densities of
liquids.
Lead shots Hydrometer can stay upright

24. Describe the suitable design to build mobile tent for Sure Heboh event which will be construct
at open space for a week. Using appropriate physics concept, suggests and explain.
Choose low density metal for frame Light weight and strong
Use hollow rod which can assemble easily Hollow rod is not heavy, but equally strong,
easy to mobile anywhere, faster to build, can
reduce the cost of construction and transport
Water proof canvas If raining, would not getting wet
Anti rust rod Can withstand rain and long lasting
Sharp end rod Small surface area, so higher pressure to
ground, yet the tent can be planted into ground
firmly and stand still
25. Explain the necessary modification for the structure of dentist chair for children that are
suitable and save for the adult.
Increase the cross-sectional area of big
piston and decrease the cross-sectional
area of small piston
To increase the output force acting on big piston
/ to lift havier adult / to increase force multiplier
of system
The wall of pipe is made up of strong alloy
to hold the fluid
To withstand the strong pressure that might
cause cracking in the channel
Change the less control into electric touch
control
To lift or lowered the chair to the desire weight
more easily and safety
The surface area of the seat enlarged To support the people with the large bodies
Use non-corrosive oil in jack So that the wall of the pipe will not be controlled
and cause leakage
26. Explain the build and design of hot air ballon wich can fly higher altitude faster and suggest
some safety aspect.
Large ballon Produce bigger buoyant / upthrust force,
increase the volume of air displacement
Many hot air burner Heat up the gas inside faster
Synthetic nylon ballon Air proof, light weight and strong material
Gas temperature is high Reduce the density of air in ballon
Total of mass is low Ballon move upward faster
Rattan basket Longer the time impact, reduce the impulsive
force to passanger when landing
Fly on early morning or late afternoon The temperature outside the ballon is cooler
compare to the inside of ballon, so the ballon
will rise higher
27. Explain the basic structure of small submarine that can be use for underwater exploration.
Strong material Does not break easily
Aerodynamic shape Reduce water resistance
Thick wall Water pressure increase with depth
High density materials Increase mass / can submerge easily
Ballast tank To increase or reduce weight
Sonar transmitter and receiver To estimate and depth
28. Suggest the design of submarine which can submerge and float in the sea.
Ballast tank are partially filled with water The submarine will partially float
Aerodynamic // streamline body To reduce water resistance
Use hard and stiff materials for body To overcome the pressure of water in the sea
Attach periscope To view surrounding area when submarine float
Use nuclear power sources to generate
power
Cheap and lasting power

29. Explain the characteristic of material to be use for making the sole of jungle trekking shoes.
Rubber sole Good impact absorber
Low density Light weight
Many stud Give extra grip
Low expansion effect Not loose easily
Excellent ability of stretch Comfortable to feet, foot can move unstressed
30. Using physics concept, explain necessary deep sea diving suit and other accessory to carry.
Choose strong helmet with thick metal and
glass to cover head
To withstand high pressure of water and protect
the head
Use thick glass in front of diver face Enable the diver to see surrounding and at the
same time able to withstand the pressureof
water
Use water proof suit and able to withstand
pressure
Due to depth, the pressure under water is very
high
Bring along gas containing mixture of
oxygen
To provide oxygen to diver for breath
Use very heavy suit The diver enable to stand on the floor of ocean
and able to fight buoyancy of water
31. Modified the passanger airplane to cargo airplane that needs to carry more laod, less use of
fuel, effenciency and safety to travel.
Increase the size of the body To increase the space
Increase the length of the wing To increase the upthrust
Increase the thickness of the body To stand higher pressure difference
Use a more powerful engine To overcome bigger inertia and do more work
per unit time
Increase the number of tyres To support higher mass or pressure while
landing
Protective bar between the cabin and the
pilot
To prevent moving object to knock at the pilot
while landing
Pilot has ejected seat during emergency To save the pilot if plane crash happened
32. Design Vacuum Cleaner
Large fan driven Inrease the spped and amaunt of airflows
Powerfull of lectric motor Inrease the spped and amaunt of airflows
Narrower inlet opening Inrease the velocity/decrease air pressure
Using a very large filter to block dust
particles while allowing air moleculs to pass
through
To have a lots of surface area and many pores
for air to flow through
Larger spaced for depositing and collecting
the dust particles
Ensure that the air flows through the filter is
not block by too many dust particles
33. Design paint sprayer
Large size of air vessel Compress more air/can exert large pressure
Rubber material for the vessel More elastic/easier to squeeze
Narrow shape of the tube Air can move with high speed
Fibre glass material for the rod Stronger and last longer
Size of nozzle is narrow at the end The paint can be sprayed evenly
34. Design hidraulic jack

Bigger crossectional area of slave piston(big
piston)
Produced higher force
Small crossectional area of master
piston(small piston)
Less forced is needed/produced bigger
pressurre
Longer handle Less forced is needed to press small
piston(master piston)
Low density of a body Lighter
Oil for liquid Non-compressable
Release valve between small and main
reservoir(reset)
Liquid can flows into small reservoir easily
when push the reset button.
35. Design hydrometer
Bulb with lead shot at the lower section To submerge the hydrometer and not overturn
Cylinder with bigger diameter at the bottom not overturn/increase stability
Cylinder with smaller diameter at the upper
section
A small reading scale can be
incorporated/inrease the sensitivity
Smaller scale inrease the sensitivity
Filled with air Inrease the beyoncy force
Glass wall Not corrode easily
CHAPTER 4
36. Most suitable design of thermometer to use in Antarctica
Use alcohol as liquid – in glass thermometer Freezing point of alcohol is -115o
C .So , it will
not freeze at low temperature
Use thin wall of bulb So it will sensitive to the change of heat
Use small diameter of capillary tube Alcohol can expand at high rate for the small
change in temperature
Use thick glass wall The loss of heat to surrounding is small
Use round glass stem Can act as magnifying glass , so the alcohol
level can be seen clearer
37. Most suitable design of clinical thermometer
Use mercury Easy to read because it colour and opaque
The scale range from 35o
C to 42o
C To measure human body heat
Small diameter of capillary tube// extra fine
bore tube
Mercury can expand at high rate for a small
change in temperature
Use thin glass wall of bulb Sensitive to change of temperature
Use round glass stem and wall Can act as ,magnifying glass. So, mercury can
be seen clearly
38. Explain the design and the characteristics of the cooking pan
Base is made of a copper Copper has a lower heat capacity it become hot
very quickly
High density of base Heavier base make the pot stable and not topple
over easily
Body is made of aluminium Low specific heat capacity becomes hot very
quickly but it low density make it overall weight
of weight lighter
Handle is made of wood or plastic High specific heat capacity so the handle do not
become hot . Safe
Choose low density material for handle Does not add much to the total weight of pot
Transparent pot cover Able to cooker to see the food. Food cover will
trap the heat
39. Suggest and explian the design of water heater to boil a large quantity of water faster ,efficient
and safely

Use tungsten High melting point,high heat energy
Coiled Longer wire,increase the resistance
High melting point Not easy to melt at high temperature
Lower rate of rusting Does not get rust easily
Use thermostat When temperatures reach 100 Celsius, the
water heater will automatically turn off
40. Determine the modification to be made for container,so the cut fruit will keep cool, remain
fresh and easily seen by customers.
Use container with high specific heat
capacity
Able to slow down the loss of heat from the
container
Place small ice packet below the bottom of
the cut friuts
The cut fruits is chill and juicy, ice able to
absorb a large amount of latent heat when
melt
Add salt to the packet of ice Foreign matter will increase the freezing point
of ice, so this will slow down the ice from
melting
White wall colour of container Can avoid absorbtion of heat from the
surrounding
The container has double wall Avoid heat from surrounding transferred easily
to container. The inside container remains cool
Transparent wall of container in front of
customer
The customer can see and choose the cut fruits
easily
41. Investigate the most suitable liquid that can be use as coolant for car engine using physics
concept.
Low freezing point liquid Will not freeze easily during winter weather
High boiling point liquid Do not easily boil when absorbing heat from
the engine
High specific heat capacity liquid Can transfer large contain of heat with a small
rise in temperature. Able to cool up the engine
Low ability to react with metal The metal part of the engine will not corrode
easily
42. Most suitable thermometer for laboratory to measure the temperature of ice and boiling point
of water
Size of the bulb is small Does not need a lot of heat to heat up the
mercury to expand
Use thin wall of bulb So it is sensitive to change of heat
Use mercury Freeezing point of the mercury is -39 degree
celsius and boling point 357 degree celsius .
Able to has a range from -10 to 110 degree
Celsius. Mercury can expand a high rate for
small change of temperature
Use thin wall capillary Able quick heat transfer from the surrounding
to the mercury. So, the thermemeter is more
sensitive
Has minimum size scale with small
division
Making thermometer a sensitive instrument
43. Modified and explain the design of an efficient solar water-heating system on the roof.
Pipe embedded in plate must be long Longer pipe will has greater surface area
which can absorb heat faster
Use metal pipe as pipe inside the plate Metal is good heat conductor , so heat will
easily transmit to water

Use insulator behind the absorber panel Insulator will prevent the heat loss
Use black absorber panel Black is good heat absorber
Cover the top of the panel with glass Heat will trap inside due to green house effect
Put the tank at higher level To give higher pressure
44. Explain the build of solar cooker oven that been use in science month competition at your
school to boil 500ml water in short time.
Build the solar cooker with shiny// silver
colour reflector inside
The light will reflect to the cooker and heat up
the water
Use metal cooker Good conductor
Paint the outside part of the solar cooker
and the cooker ( contain water ) with
black colour
To absorb
Wrap the cooker with plastic or glass Avoid heat from release to sorrounding
To trap heat, the temperataure will
increase
To absorb heat, the water boil faster
45. Suggest the design of heating system in the house and characteristics of heating agent. The
house use central heating system with boiler, radiator and pipelines.
Use strong material Not easily break
Use metal pipe with good heat conductor Increase the rate of heat transfer
Increase length of cooling coil Can transfer the heat faster to surrounding
Use greater boiling point liquid Liquid not easily change into vapour
Low rate of rusting material Long lasting, not easily rust
The bigger size of radiator fan Can blow and cool down larger area
Pipe in coil structure is used Increase the time of floe and increase the
quantity of haet transferred.
46. Suggest the characteristic of material to build food container which can keep the food
warm.
Food container should made of low
density material
Lighter , the container able to be move from
one place to another.
Melting point of container should be
high
To prevent the container from melting up
when hot food is store inside
Specific heat capacity should be high So the container will not get hot easily. Safe
to touch and handle.
Thermal conductivity is low.i Good heat insulator , to ensure the heat not
loss and the food remain hot.
Double wall To prevent hest loss.
47. Explain the characteristic and design of thermos flasks to maintain hot water.
Use hollow plastic stopper Able to trap air as air is poor heat
conductor.so,less heat loss through stopper.
Vacuum space Prevent heat loss through conduction or
convection
Has double wall Has vacuum in between heat not easier pass
through the wall of thermos.
Double walled tube coated with shiny
paint
Shiny surface reflect heat from the wall of
thermos flasks back to water.so the water
remain hot.
Double walled made of glass Glass is bad conductor.it will reduce heat loss.
48. Explain how the design of radiator of the car and characteristic of cooling agent which can
absorb heat at short time,
Increase the length/area of cooling coil Can transfer the heat faster to the surrounding
Increase the number of fin blades Can cool down faster

Use larger fan Can cool down larger area
Use cooling agent liquid with greater
boiling point
It won’t boild easily in high temperature
Use cooling agent liquid with higher
specific heat capacity
Able to absorb large amount of heat
CHAPTER 5
49. Determine and explain in the build of magnifying glass to be use for enlarging the image of
stamp
Choose convex lens The image will magnify
Excellent clarity of lens The image is clearer
Small focal length Able to focus nearer
Medium diameter of lens Able to be hold by hand to identify the stamps
The object is place less distance than
focal length
The image form is magnify, virtual and upright
50. Explain the suitability of the mirror that be use in shop to watch over the customer
Use convex mirror Wider field of view
Greater reflectivity of material Clearer image
Choose a bigger size of mirror Enable wider view and sharper image
Place the mirror at the corner of shop
ceiling
Easier to look at and won’t disturb the
customer pathway
Low density Lighter to hang up
51. Design fibre optic
Use refractive index of outer layer is less
than the refractive index of inner layer
So that total internal reflection can happen in
the fiber optic.
Use high flexibility material so that it can be bend easily
Use strong material do not break easily
Use thin material Lighter // can be use in small area
Low density material Lighter
52. Determine and explain the build of microscope using lens P and Q with focal length of 15 cm
and 5 cm respectively. Suggest modification that need to be done to get brighter ang bigger
image.
Suggestion Explaination
P as eye piece and Q as objective lens Focal length of P is longer than Q
Fo < u <2fo To produce real, inverted and magnified image
Adjusted so that u < fe To produce virtual. Inverted and bigger image//
to acts as a magnifying glass
Distance between lenses > fo + fe To produce bigger image from the eyepiece // to
increase the magnification
Store in a cool and dry place To avoid formation fungus at the lenses
Use more powerful// shorter focal length
lenses
To produce bigger image
Use a lamp near the object// use bigger
diameter of objective lens
To produce brighter image
53. Explain the suitable characteristic of the mirror to be use as outdoor safety mirror at the corner
of the road
Use convex mirror Wider field of view
Excellent weather resistance Able to withstand bad weather
Excellent impact resistance of material Save cost, everlasting
Bigger size mirror To enable a wider view and sharper image

Greater reflectivity of material Clearer image even in bad weather
Place at the sharp road corner , at
bending road
To minimize from accident occur, to enable
motorist see the oncoming traffic
Small roof Protect from rain drop for better image
54. Detemine and explain the build of Astro disc using appropriate physics concepts.
Choose convex curve parabolic The signals come can be focus at one point
All signal are focus on focal point Better reception
Smooth surface of disc Better reflection
Locate the disc at high and facing towards
satellite
No obstacle, better signal
Clean surface of disc, no water drop or dirt Better reflection, almost 100% reception
receive by feed horn
55. Modified the slide projector that need to be place in school hall and can be seen by many
student with clearer image.
suggestion Explaination
Use higher power bulb Higher intensity of light or more light produced
The filament of the bulb is at the focus
point of the concave mirror
The light focuses at one point. // parallel ray
can be obtained after reflection by concave
mirror
More curvature More light to be reflected (upward) // less light
toward other direction other than upward
Lens between f and 2f To produce real ang enlarge or bigger images
Increase the distance or further away the
screen
Larger image produced
Electric fan operates during and after the
lamp is switches on
Cooling system to stabilized the temperature
(heat energy produced by filament bulb) to
increase the projector lifetime
Use condenser mirror To concentrate more light to the slide
Use a concave mirror instead of plane
mirror
Focus the light directly to the lens // increase
the intensity og light
Place the filament at centre of curvature
of the converging mirror // use high
powered lens
Light goes directly from the lamp and reflect
back on the same path // increase the intensity
of light toward the transparency // to get
brighter image
Use heat filter To absorb excess heat to the transparency
56. Determine and explain the build of telescope using lens J and K with lens K is thicker than lens J
which produce bigger and clearer image.
Suggestion Expalanation
 C hoose lens K as eyepiece lens
Lens K is thicker than lens J
 Light ray is refracted more in lens K than
lens J, focal length of lens K is shorter than
lens J
 Therefore the thickerthe lens, the greater
the refraction of light and with that the
shorter the focal length of a lens will be
 Choose lens J as objective lens
Use bigger diameter lens as objective
lens
Characteristics of objective lens for telescope
is
 Has larger surface area which allow
more light enter
 Has a longer focal length
Use low power convex lens as the
objective lens
 Magnification of telescope =f0/fe
Low power lens has a longer focal length ,fo
higher, magnification higher
Use high power convex lens as the eye
lens
High power lens has a shorter focal length,fe
higher, magnnification higher
Use bigger diameter of objective lens More light permitted to enter the telescope
and a clearer image is seen
CHAPTER 6

57. Design a good beach
near the bay divergence of the waves energy /calmer
High retaining walls Over flow
To reflect the waves from the shore
Reduce direct impact of the waves on the
shore
Wall from concrete reduce erosion are built
Concrete barrier structure with a gap Waves passing through the gap will be
diffracted in the children’s area.
-reduce amplitude
Tambak laut supaya lebih cetek Reduce speed
More number of tree Diffraction occur will reduce tha amplitude
Uneven surface of retaining wall Reduce energy
58. Suggest and explain how ordinary fishing boat can be upgrade to the new boat which complete
equipment to detect the crowd of fish.
Attach radar system to the ship
a) Ultrasonic transmitter
This equipment needs to detect crowd of fish
and for measurement the depth of the crowd
of fish
-Use to produce ultrasonic pulses
a) Microfone reciever To detect ultrasonic pulses
b) CRO -To measure the depth of fish by calculating
d=vt/2; d=depth, v=velocity, t=time
Use ultrasonic wave -Ultrasound not produce sound
-Ultrasonic wave has higher frequency, more
energy, so it can move further
Use high energy wave The penetrating power is higher
59. Explain the suitable design or method to build quality concert hall.
Cover the hard wall with soft board or
thick curtain
Soft surface can absorb sound and reduce
reflection of sound
Place the wall with hole or egg carton
design
Can reduce reflection of sound so sound will
be clearer/reduce echo
Fixed 2 loud speaker in concert hall Loud speaker can act as coherent sources for
constructive inteference
Arranged the sit at antinodal place Strong sound can be heard
Use glass or mirror hall which is the type
which are not easily broken
Sound with high frequency might break the
glass
Use special computer to generate sound
wave which produce destructive
inteference
Audience can enjoy better presentation
without disturbance
60. Explain the suitable design of retaining wall to protect the ship at the harbor
Suggestion Explaination
Build concrete retaining wall Can withstand impact of the wave, difficult to
crack
Retaining wall should be curved and
uneven surface
Prevent reflection of wave back to the ship
Build retaining wall in front of the bay The wave are calmer at thr region
Retaining wall has gap Diffraction will occur
The gap at retaining wall is
narrow( smaller than wave length)
The greater the curvature of wavefront will
occur. Amplitude after passing gap is smaller
There are slope at the bottom of retaining
wall
At shallow region, the wavelength of wave is
smaller, so the velocity of the wave smaller
Retaining wall should be build higher To ensure no spill over of wave
Build the jetty at bay The wave at bay is calmer

61. Explain the characteristics of parabolic radar system to detect signal from satellite
communication.
Large diameter size of parabolic disc Able to receives more electric signal
Type of wave transmited is Microwave Has high frequency, high energy, short
wavelength so it is easy to be reflected
The distance of the signal receiver from
the centre of parabolic disc is the same as
the focal length
The signal can be focus to the centre of the
parabolic disc
Place parabolic disc higher from the
ground
The signal with not be block by trees or
anything and the signal easy to be detected
Place parabolic disc at clearplace No signal disturbance
CHAPTER 7
62. Suggest the suitable lamp that can be use in the library, cheaper yet become the room
brighter
Lamp with parallel circuit If any lamp were burn out, others can still be
used
Attach shiny reflector Can reflect light more, no need to install more
lamp, the room will become brighter.
Low power lamp Safe cost
High efficiency lamp // fluorescent The room looks brighter
Long life span lamp No need to replace often
Low price lamp Save money
63. Explain the modification of menthol bulb lamp to efficient lamp to be use in study room.
Use the fluorescent lamp not a
filament bulb
Fluorescent lamp use less power and economic
(consume less power) compare to filament bulb.
Bigger cover with white colour Less reflection on eyes and absorb less heat
energy and good heat reflector
Use the adjustable stand or portable The height of the lamp can be adjusted can be
used anywhere
Connect with the earth wire Avoid short circuit and damage on the bulb
Use an energy saver lamp Produce same brightness with less power
consumption
64. Suggest the suitable design of fuse to protect an electrical equipment which is label
240V,2400W
Thin fuse wire Less space/to carry a limited electrical current/less
mass hence low heat capacity/shorter time to
heat up to melting point and blow
Ceramic cartridge Can withstand higher temperature because spark
created by high voltage.240V can be huge
Fuse rating is 13A Maximum rating must be sligthly higher than
normal current
Low melting point For fast blow/melting faster when excessive
current flow/easy to cut the current flow
Low specific heat capacity The fuse wire easily heated,melt and break the
circuit
Metal is used Good electric conductor
Resistance to oxidation Does not interface with other function
65. You have to choose one of the cables to be used in the National Grid Network. Explain the
suitability of each of the characteristics of the cables.
Diameter should be large To reduce the resistance of the cable
density should be low The cables will be lighter and can be

supportedsecurely
The rate of expansion should be low So thre is less expansion and less sagging in the
cables during hot days
The melting point should be high So the cables does not melt in high temperature
66. Explain the characteristic of electric pylon and the cable taht been use for electric transmission
Material: steel alloy Strong,will not break easily
V shape steel alloy Not too heavy
Trust and supprt join Can support bigger weight
Made from small diameter and laminated
wire
Reduce addy current
Cable made from low density material Cable is not heavy/ light weight
67. Investigate the characteristic of electric oven that can toast more cupcakes at less time
The space inside oven is build bigger It can fil up 180 slices of bread
Increase the number of resistance heater
at the top and bottom
So it can supply enough heat
The wall is made of good insulator Tyhe heat will not lost to surrounding
Fix a fan inside the oven Heat energy releaswed can spread uniformly
in oven
Internal space of oven is painted silver So the heat will radiated at wall and reflected
back completely
Fix the step up transformer Oven can receive higher voltage and can
function with higher power
68. Explain the designof electric kettle
Material of heating is made from nichrome To produces high heat energy
High number of loop To increase surface area so that more heat is
released
Use high power To produce more heat energy in the coil
High melting point coil Nit easy melt under high temperature
Low rate of rusting Does not get rust easily
Use thermostat When temperatures reach 100o
C
3 plug in If short circuit the overload current flows to
earth(for safety reason)
69. Design incubator used to hatch eggs
Parallel circuit When one bulb damage the another bulb still
function/heat can distributed uniformly
Multi storey rack More eggs can be arranged
Using fan heat can distributed uniformly
Bulb with same brigthness and
power
heat can distributed uniformly
Using alarm To ensure that correct timing is employed in the
hatching of eggs
70. Design circuit for cabin or house
connected in parallel Allow each electric appliances to be switched on
and off independently
Fit fuse at the live wire in the fuse
box
To stop the flow of current by melting when a
high voltage of electric current flows through the
circuit // switches itself off very quickly if the
current exceeds e.g. 15A (for 15A mcb)
Earth connection to the metal case of
electrical appliances
Earth wire connected to earth, so that when a fault
occurs and a current flows through the live wire

and the earth wire, the fuse in the live wire will
blow and cut off the supply. It will protect a person
who may touch a faulty or live appliance
Use low power lamps / install
fluorescent lamp
To save the energy
Regularly cleaning and removing dust
from the air filters of air conditioners//
Do not put more water in a kettle
than needed for hot drinks
To save the energy
CHAPTER 8
71. Suggest modification that need to be done on dc motor to increase efficiency of the motor.
Low density material Coil hass smaller mass/ lighter
Increase the number of
turns in the coil
Can increase magnitude of force/ higher electromagnetic field
strength
Use high strength of
magnets/ Add more
magnets
Increase the strength of magnetic field
More segments Coil rotates smoothly
Increase the magnitude of
current
Can increase the magnitude of force/ can increase the
strength of magnetic field
72. Investigate the design and the characteristic to improve the efficiency of transformer.
Use soft iron core Easy to magnetized and demagnetized
Laminated core Less eddy current or reduce energy lost
Use thick wire Reduce the resistance or more current flow
Use copper wire to make coil Low resistance or reduce the lost of heat
Wind the secondary coil on top of the
primary coil
Reduce leakage of field lines
73. How to design a moving coil ammeter that can function better and able to detect small change
of current?
Use stronger magnet Strong magnetic field or larger rotation
Use curve magnet or concave Produce radial magnetic field/to get linear scale
Use cylindrical core To supply uniform magnetic field
Use soft iron core To concentrate the magnetic field
Use linear scale The angle of rotation is linear
The sensitivity of moving coil
galvanometer can be increased
by increasing the strength of the
radial magnetic field
Increase the force between the current carrying coil and
magnetic field
Using hairspring of lower
stiffness
Smaller opposing force to stop turning of coil
Use lighter pointer Smaller inertia easier to move
Use a coil of a lighter mass Smaller inertia able to move easily
Increase the area of coil More changes of magnetic flux,a bigger force are
produce
74. Suggest and explain the build of adaptor to charge the 8V handphone from 240V power supply.
Use step down transformer Able to reduce voltage
Ratio of turns 30 : 1 // 240V:8V Can reduce voltage from 240V to 8V
Use four diodes Full wave rectification
Full wave rectifier To convert au current to dc current
Using a capacitor To smooth output current (steady direct current
CHAPTER 9

75. Suggest and explain the build of adaptor to charge the 8V handphone from 240V power supply
Use step down transformer Able to reduce voltage
Ratio of turns 30 : 1 // 240V:8V Can reduce voltage from 240V to 8V
Use four diodes Full wave rectification
Full wave rectifier To convert au current to dc current
Using a capacitor To smooth output current (steady direct
current
76. Consult and modified the automatic switch light (diagram A) above which can switch on at
night and switch off during morning to be automatic switch on fire alarm when there are fire ,
explain using diagram and the function of component.
Change R1 to termistor Thermistor can be detect heat from fire
Change LED with alarm// siren Able to produce sound of alarm if fire is
detected
Change LDR with R1 During fire, R1 has greater resistance compare
to LDR so, no current flow
When the temperature is high, the resistance of thermistor is low. This will increase the voltage
acroos R1. So, currnt will flow to the base of transistor , than the transistor is switch on followed by
greater increase in collecter current. The alarm will switch on.
77. Suggest the modification need to be done to the circuit in Diagram C so that it can function as
automatically fire alarm switch that need high voltage.
Replace LDR with thermistor To detect heat when temperature is high
Replace bulb with siren/bell To produce sound
Connect relay switch to output transistor To switch on the siren
Interchange the position of resistor R and
thermistor
To increase base voltage//voltage across
R//base current
Use 240 V power supply Siren is function as high voltage
78. Modified the circuit 240V and Np = 4000 turns circuit to switch on 12V d.c radio.
Step-down transformer Capable of reducing potential difference /
voltage
Ratio of turns 20 :1 // 240:12 Np = 4000
turns and Ns = 200 turns
Reduce potential difference 240V to 12V
Using four diodes Full wave retification
Using a capacitor To smooth out output current // produce
output to steady direct current.
79. Moving coil microphone
12V,24W

use thin diaphragm Easy to vibrate
Use strong material Not easy to break
More number of turns of coil Increase the rate of change of magnetic flux linkage //
The magnitude of the induced current or is also
increased
Thicker diameter of wire of coil reduce the resistance of the coil
Using more powerful magnet to increase the strength of the magnetic
field.//Increase the rate of change of magnetic flux
linkage//The magnitude of the induced current or
induced electromotive force is also increased
CHAPTER 10
80. Explain the suitability of characteristic of radioisotopes to be used as treatment in brain tumor
radiotherapy?
Short half life Radioactive is dangerous substance,
short half lfe can decay faster
Gamma ray radiation Gamma can kill cancerous cell and can
penetrate skin of patient
Low ionozing power Minimum damage to tissue organ
Liquid state of matter Easy to dissolve
High penetrating power Can penetrate easily
81. Suggest and explain the safety ways, which are required when handling radioactive substance.
Use thick lead box Radioactive rays evem gamma cannot pass
through
Use forceps / robotic hand Avoid direct touch
Wear photographic film Able to detect exposure radiations
Wear plumbum safety suit To protect the body from expose to radiation
Use siren Faster warning when leakage
Packed into concrete drum and buried
underground
Prevent the radioactive waste discharge to
environment
Always place GM detector nearby To detect the amount of radioactive nearby,
for safety
Label the radioactive container with
symbol
Easy to detect radioactive substance
82. Explain the suitability of characteristic odf radioisotope to be use in controliing the population
of pest
Use gamma ray Able to mutate the insect
Solid state of matter Easy to handle
Long half life Last longer
High penetrating power Able to penetrate thick object/material
High ionizing power Able to change// mutate the biology of insect
83. . Explain the suitability of characterisitc of radioisotopes to be used in th trace of water
pipeline.
Short lhalf life Radioactive is dangerous substance, short half
life can decay faster
Few hour half life - Enough time for worker to detect the
pipe leakage
- Radioactive uis dangerous
Beta particle or Gamma ray radiation Can penetrate pipe and soil, can be detected
Liquid state Can be inject and dissolve into water
84. Suggest the design of nuclear reactor.

Use uranium-235 Use as nucler fuel
Nuclear fission A lot of heat will produce
Boron or Cadmium rad use as control rods To control the rate of nuvlear fission and to stop
the radiation
Use moderator (graphitr) To slow the motion of neutron to the best reaction
rate. So the rate of nuclear fission can be
controlled
Bulid thick concrete wall Lead or thick concrete wall can prevent the
escape of radioactive rays, keep the radiation
inside the reactor
Coarbon dioxide or water is use as coolong
agent
To remove heat of reaction for turbine generator.
This produce steam as heat carrier
Use steam To turn the turbine and able to generate current
85. Explain the suitability of charactersitic of radioisotopes to be used in sanitiza medical equip,ent
Gamma ray Able to kill ant virus/ bacteria
Longer half life No need to change radioactive frequently
Silid state of matter Easy to handle
High penetrating power Able to penetrate any equipment to sanitize
86. Explain the suitability of characteristics of radioisotope to be used in detecting the position of
blood clot in veins (Deep vein thrombosis)
87.
E
xplain the suitability of characteristics of radioisotope to be use in the trace of blockage in the
kidney patient.
Use Iodine-123 Used as nuclear imaging tracers to evaluate
the anatomic and physiologyc function
Gamma ray Able to penetrate trough body, bones and be
detected
Low energy Do not cause serious damage in cells
Liquid state of matter Easy to inject to patient body
Short half life Active in body in short time
88. Explain the suitability of characteristics of radioisotope to be use in control the thickness of
paper in factory
89. Explain the suitability of characteristics of radioisotope to be use in control the thickness of
aluminium sheet in factory.
Long half life Can be used for long time, no need to replace
frequently7 so, it save cost
Gamma ray Can be penetrate aluminium sheet and be
detected
Solid state of matter Easy to handle, does not spill
Use liquid state of matter Able to inject into patient body, dissolve easily
Short half life Active in body in short time
Use beta ray Able to penetrate skin
Low ionizing power Minimum damage to tissue organ
Long half life Can be used for long time, no need to replace
frequently so, it save cost
Beta ray Can penetrate paper and be detected
Solid state of matter Easy to handle

MAKING DECISION-SECTION C
90. The transmission of electricity over the National Grid Network uses high voltage cables. You are
assigned to study the characteristics of cables which could be used as transmission cable.
Table 12 shows the characteristics of four transmission cables. Determine the most suitable
transmission cable to be used and give reasons for your choice.
Cable
Resistivity /Ωm-
1 Density / kg m-3
Cost Rate of thermal expansion
P 3.0 x l0-7
5 x l05
Low High
Q 1.8 x l0-8
2 x l03
Medium Low
R 7.5 x l0-7
8 x l02
High Medium
S 7.0 x l0-8
4 x l03
Medium High
Jawapan
Low resistivity To reduce heat loss in the cables
Low density The cables will be lighter
Low cost Cost of project will be lower
Low rate of thermal expansion The cables will not expand under hot weather
Cable Q Low resistivity, low density, medium cost, low rate
of thermal
expansion
91. You are required to build a hydrometer that can be used to measure densities of
concentrated acids.Table 11.1 shows the characteristics of 4 types of hydrometers L, M, N and
O. Decide which hydrometer is most suitable and give reasons.
Hydromet
er
Type of
material of
hydrometer
Diameter of
capillary tube/
cm
Density of
shots/ kgm-3
Diameter of
bottom bulb/ cm
L Plastic/Plastik 0.5 1000 1.0
M Plastic/Plastik 2.0 1300 3.0
N Glass / kaca 0.5 9800 3.0
O Glass/ kaca 2.0 8000 1.0
Jawapan
Material made from glass Glass does not corrode with acid
Small diameter of capillary tube To increase the sensitivity of the hydrometer
High density of shots Makes the hydrometer stays upright
Big diameter of bottom bulb To obtaine a bigger upthrust.
Choose N N is made from glass, has small diameter of
capillary tube, high density of shots and a big
diameter of bottom bulb
92. As a researcher , your duty is to study the characteristics of a material to make a water
heater. You are given four choices of metal type T, U,V and W. The table below shows the
characteristics of the four metals.Determine the most suitable metal to be used as the material
to make the heater and give your reasons.
Jawapan
Smaller surface area the resistance is higher
High melting point not easy to melt
Low specific heat capacity the temperature arises shortly
Long (coiled) metal to increase the resistance
Choose V because it has,smaller surface area, high melting
Metal
The cross sectional
area
Melting
Point
Specific Heat
Capacity
Length
T Smaller Low High Long
U Larger High Low Short
V Smaller High Low Long
W Larger High Low Short

point, low specific heat capacity and long metal
93. You are given four choices of metals P, Q, R and S. The table below shows the characteristics
for the four metals. Determine the most suitable metal to be used as the material to make the
boat and give your reasons.
Metal Shape Density
Specific Heat
Capacity
Strength
P Streamlined 900 Low High
Q Oval 452 High High
R Circle 387 Low High
S Streamlined 500 High High
Jawapan
Characteristic/cirri Reason/Sebab
Streamline / larus reduce the resistance of water/
Density /ketumpatan rendah higher buoyant force/ daya apungan
tinggi
Specific heat capacity high / absorbs heat slowly/serap haba dengan
perlahan
High strength / Kekuatan tinggi Difficult to damage / sukar rosak
Choose S because its streamline,low density, high
specific heat capacity and high strength
94. A student plans to fix a lamp in his room. Table 12.1 shows the features of 4 different types of
lamps. Explain the suitability of each feature in Table 12.1 and then determine the most
suitable lamp to be used. Give a reason for your choice
Type of lamp Power Efficiency Life Span Price
Compact fluorescent
lamp
18 W 50 % 7000 hours High
Filament lamp 75 W 12 % 1000 hours Low
Long fluorescent lamp 20 W 45 % 14000 hours Medium
Round fluorescent lamp 24 W 40 % 10000 hours High
Jawapan
Low power lamp Safe cost//electric bill
High efficiency The room looks brighter//high output power//less
power wastage
Long life span No need to replace often
Low price Save money/cost
Long fluorescent Low power with highest efficiency, long hours of
life span and low price
95. Table 11.1 shows 5 materials which can be used to make an optical fibre. You are asked to
investigate the characteristics of the materials in Table 11.1 which could be used to make the
optical fibre.
Explain the suitability of each characteristic and hence, determine the most suitable material
to be used to make the optical fibre. Give a reason for your choice.
Material Refractive
index
% of light energy
absorbed
Rigidity Strength
P 1.75 2 % Strong Weak
Q 1.80 10 % Weak Strong
R 1.70 2 % Weak Strong
S 1.52 3 % Strong Strong
T 1.48 10 % Weak Weak
Jawapan
High refractive index Total internal reflection can occur easily
Small amount of light energy being
absorbed by the material
The object under observation can be seen clearly //
more light can be transmitted
Material with weak rigidity The optical fibre can be bent easily

Material with great strength The optical fibre can last longer/not easily spoil
Material R High refractive index, low % of light energy
absorbed, weak rigidity and great strength
96. You are asked to investigate the characteristics of hot air balloon as below. Explain the
suitability for each characteristic for the hot air balloons and then determine which hot
balloon will move up the fastest into the air. Give a reason for your choice
Jawapan
Characteristic Explaination
Volume of the balloon is high Displace a larger amount of air/
Produce a higher buoyant force.
Density of the balloon material is
low
Lower mass/Light
Gas temperature is high Produce a maximum expansion of balloon.
Total of mass is low Upwards resultant force is higher/ Balloon move
upwards faster.
Choose Q
Because it has a high volume,the density of the balloon
material is low,the gas temperature is high and the
total mass is low.
97. Table 11.1 shows the characteristics of five types of materials that can be used for making the
soles of the trekking shoes. You are asked to study the characteristics of the materials shown in
Table 11.1. Explain the suitability of each characteristics in Table 11.1 and then determine the
most suitable material to be used. Give a reason for your choice.
Type of
material
Density
(Kg/m -3
)
Number of studs x Area
of 1 stud
Expansion
effect
Ability to
stretch
P 820 6 x 30 cm2
Low Good
Q 700 8 x 30 cm2
Low Good
R 720 5 x 30 cm2
Medium Average
S 750 4 x 30 cm2
High Poor
T 880 3 x 30 cm2
High Poor
Jawapan
Characteristic Reasons
Low density Small mass/light
Many/fewer/very few studs Gives extra/higher grip
Expansion effect is low Always fits/Does not loosen when hot.
Ability to stretch is good Less stress on the feet/Can be pushed in all directions/
Can walk on uneven surface.
The most suitable material is Q Because it has a low density,many studs,low
expansion effect and good ability to stretch.

98. Table 12.2 shows the characteristics of five radioisotopes P, Q, R, S and T. As a factory
engineer, you are required to determine the most suitable radioisotope that can be used by the
system to ensure the volume of guava juice is uniform.Study the characteristics of all 5
radioisotopes and explain the suitability of the aspects.Determine the most suitable
radioisotope and give the reason for your choice.
Radioisoto
pe
Radioisoto
p
Half life
Separuh
hayat
Types of ray
Jenis sinar
State of
matter
Keadaan
jirim
Ionising power
Kuasa
pengionan
P 7 hours alfa solid high
Q 10 days beta liquid moderate
R 100 days gamma solid low
S 10 years gamma liquid high
T 30 years beta solid low
Jawapan
99. You are assigned to investigate the design for the location to keep the boats and the
characteristics of the retaining wall as shown in Diagram 12.2 based on the following aspects:
- the location to keep the boat
- material used for the retaining wall
- the height of retaining wall
- size of slit
Explain the suitability of the location and the characteristics of the retaining wall and
determine the most suitable design to keep the boat safely.
Jawapan
Bay Wave is calmer
Concrete retaining wall Stronger/ / lasting
High wall Prevent high wave
Smaller opening/aperture / slit of
retaining wall
Diffraction obvious //low wave energy
Choose P
At bay, concrete retaining wall , high wall and smaller
slit
Characteristics Explanation
Has a long half-life Can be used for a long time hence save cost
Emits beta Can penetrate box and liquid and is less
dangerous than gamma
Solid form Easy to handle and contain.
Low ionising power Does not change the state and taste of juice.
Radioisotope T It has long half life, emits beta, in solid form and has low
ionising power.

100. Diagram 11.4 shows five designs of ‘Newton’s Cradle’, P, Q, R, S and T, with different
specifications. You are required to determine the most suitable design to make the ball at the
end swings up to higher level and at bigger speed. Study all the five designs from the following
aspects:
− The arrangement of the balls − The type of material used to make the
balls
− the number of string used to hang the balls − the position of the ball to start the
oscillation
Jawapan
The balls touch each other This will reduce losses of energy which will reduce the
speed of the
balls
The type of material used to
make the
balls is steel
Steel balls are hard and produce highly elastic collision.
Energy can
easily propagates through the intermediate balls.
Two strings used to hang each
ball
This string arrangement restricts the balls’ movements to
the same plane. the position of the ball to start the
oscillation
High position of the ball High potential energy and will change to high kinetic
energy. The last end ball will swing at bigger speed.
The most suitable design is Q
because the ball s touch each other, made from steel, use
two strings attached to each ball and the initial position of
the ball is high

Modification Physics SPM

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