Rockets internet.ppt
- 1. Rockets and Newton's laws Up, up and away
- 2. What we are going to achieve today Understand Newton’s second and third laws Understand how a rocket travels using an action reaction force. Be able to use the formula; Force = Mass x Acceleration. Create your own rocket that uses a reactionary force . Use Newton’s Laws to explain why three types of rocket travel at different speeds.
- 3. Big Questions! How does a rocket get off the ground? Why is a rocket shaped like a rocket?
- 4. Newton's 3 rd law…. Every force has an equal and opposite reaction that acts on a different body, so the force produced from the water coming out of the bottle, pushes the bottle in the opposite direction.
- 5. Newton’s third law A force cannot exist on its own – there is always a second force acting against it . These pairs of forces that act between two objects are sometimes called action–reaction pairs . If object A exerts a force on object B, then object B exerts an equal but opposite force on object A.
- 6. What happens when the rocket is accelerating, are the forces balanced or unbalanced? If an object is accelerating, the forces on it must be UNBALANCED.
- 7. What is Newton’s second law? If the resultant force acting on an object is not zero, all the forces are said to be unbalanced . the speed of the object may change – it may either increase or decrease the direction of motion may change.
- 8. Rail Road Toffee Rocket When are the forces balanced? Where are the forces unbalanced? How is the rocket car pushed forward?
- 9. How is movement calculated from force? The resultant force acting on an object is related to the object’s mass and acceleration. These three factors are linked by the following equation: Resultant force is measured in newtons (N). Mass is measured in kilograms (kg). Acceleration is measured in metres per second per second (m/s 2 ). force = mass x acceleration
- 10. Using a formula triangle F M A
- 11. Task Complete F=ma questions Newton’s 2 nd Law What is the force on a 5kg mass accelerating at 2m/s/s? What is the force on a 25kg mass accelerating at 0.25m/s/s? What is the acceleration when a force of 20N is exerted on a 3kg mass? What is the acceleration when a force of 45.6N is exerted on a 3kg mass? What is the mass when a force of 60N makes something accelerate at 0.25m/s/s?
- 12. Balloon Rockets The challenge is to make your rocket go the furthest ; the speed of the rocket is not relevant. What is the best way to control the thrust ? What is the best way to balance your rocket ?
- 13. How does the mass of the particles affect the thrust? You have seen a water rocket, made an air balloon rocket and seen a real rocket launch! Can you explain the reason why these different methods create different amount of thrust? Remember F = ma Every action has an equal and opposite reaction. Think about the force on the particles.
Editor's Notes
- #6: Teacher notes It might be worth pointing out to students that action-reaction pairs are not the same as balanced forces – while the latter act on just one object, the former act on two separate but interacting objects. Newton’s third law is sometimes written as: “ For every action, there is an equal and opposite reaction.”