1. How do objects move at a steady speed?
Steady Motion
How do objects move at a steady speed?
Starter:
Describe the forces acting on a car moving at a steady velocity of 60mph, forwards.

2. Revision card
Make a revision card for momentum.

3. 6 mark question
Use the idea of momentum to explain why cars are built with crumple zones.
Marks
SPAG
What a crumple zone is/ where they are on a car.
How a crumple zone reduces the force on a person.
Use of the correct momentum equation.
What happens if no crumple zone.

4. Learning Outcomes
explain that, when an object travels at a steady velocity, there is no change of momentum.
2) explain that no resultant force is required to keep an object moving in a straight line at a steady speed

5. Speed – Time – graph Speed
For each of the 4 stages, draw a force diagram to show what is happening. C B D A
Time

6. Mini Plenary worksheet.
explain that no resultant force is required to keep an object moving in a straight line at a steady speed

7. What are these strange people trying to do?
Curling

8. On the floor
Soon it will stop. Because of friction, the stone begins to slow down as soon as he lets go.

9. On Ice
But it still slows down and stops. Ice has less friction. the stone does not slow down as quickly.

10. On “perfect” ice the kettle never stops, it stays at a steady speed
On “perfect” ice the kettle never stops, it stays at a steady speed. Why?
This imaginary ‘perfect’ ice has no friction at all. The stone will not slow down or stop. it will keep on going at the same speed for ever.

11. Lets investigate - Which surface is closest to “perfect ice”? Surface
Force needed to move object (N)

12. Steady Speed and Momentum
Look at the equations for momentum and work out why at a steady speed, momentum of an object does not change.

13. 6 mark question
Use the idea of momentum to explain why cars are built with crumple zones.
Marks
SPAG
What a crumple zone is/ where they are on a car.
How a crumple zone reduces the force on a person.
Use of the correct momentum equation.
What happens if no crumple zone.

14. Round the Room Questions

15. Task
Write 5 momentum questions of your own, and produce a marking scheme.
Swap with neighbour, complete their questions and WWW/ EBI them.

16. Look at the objectives – how are we doing?