Gravity and Motionnnnnnnnnnnnnnnnnnn.ppt
- 2. Isaac Newton • Isaac Newton was the first person to hypothesize that the force that pulls an apple to the ground also pulls the moon toward Earth, keeping it in orbit.
- 3. Gravity • Gravity is a force that attracts all objects toward each other. • The force of gravity is measured in units called Newtons (N). • http://www.brainpop.com/ (Gravity)
- 4. Mass vs. Weight • Mass- is the amount of matter in an object • Weight- is the force of gravity on an object • The greater the mass the greater the force (weight)
- 5. Weight • With out air resistance everything falls at the same speed. It’s called Free Fall. • It just so happens that on earth free fall has an acceleration of 9.81 m/s2 • This means we can caclualte weight!
- 6. Wieght • Weight is a force so……. • Weight is equal to mass time acceleartion of free fall. • W= mg g = 9.81m/s2
- 7. Gravity of two objects • Any two objects will exert a gravitational pull on each other. • So why does the earth not move towards us??
- 8. Gravity • The strength of gravity between two objects depends on two factors: • 1. masses of the objects • 2. distance between the objects
- 9. Gravity The greater the masses, the greater the gravity between the objects. The greater the distance, the less the gravity between the objects.
- 10. Law of Universal Graviation • Newton realized that this relationship between mass, distance and gravity could be mathematically shown. • F = G m1m2 d
- 11. Why do Earth and the moon remain in their orbits? • Inertia and gravity combine to keep Earth in orbit around the sun and the moon in orbit around the Earth. • A combination of gravity and inertia keeps the moon in orbit around the Earth. If there were no gravity, inertia would cause the moon to travel in a straight line. If only gravity existed, the earth would be pulled into the sun.
- 13. Your weight on other worlds • http:/www.exploratorium.edu/ronh/weight/