1. TITLE: P2 Revision 11A5 Objectives How do we measure the extension of an object when stretched? – grade C What is the spring constant of a spring? – grade C What is Hooke’s law? – grade C KEY WORDS: Stretch Squash Extension Energy Spring constant force Newtons Metre Extension Proportional Limit of proportionality Outcomes: Use the revision PowerPoint to complete the set activities in preparation for your mock examination Complete the terminal velocity card sort with Mrs Potts

2. What is meant by Resultant Force? (Use to help with slide 3 and 4) The differences between the forces acting on an object to create an overall single force. Resultant Force = zero when an object is stationary or at a constant speed if moving Resultant Force = not zero when an object is accelerating or decelerating

3. What is the resultant force for each car? A = B =

4. DESCRIBE the motion of each car and EXPLAIN why? A = B =

5. Why have speed limits? The faster a vehicle is driving, the longer it will take to stop – the overall distance this takes is the stopping distance. stopping distance = t_______ distance + b_____ distance

6. What affects thinking distance? The thinking distance is the distance a vehicle travels in the time it takes for a driver to react to a situation and apply the brakes. What factors will affect thinking distance? – 3 images

7. Is a tired driver as dangerous as a drunk driver? http://www.bbc.co.uk/learningzone/clips /risks-of-driving-when-tired/8323.html http://www.bbc.co.uk/learningzone/clips /risks-of-driving-when-tired/8323.html

8. What affects braking distance? The braking distance is the distance a vehicle takes to stop once the driver has applied the brakes. What factors will affect braking distance? – 3 images

9. Factors affecting stopping distances

10. What does the graph show?

11. What is the difference in speed of the cars?

12. Velocity time graphs – label the points A B C Acceleration Deceleration Constant speed A B C

13. Investigation What is meant by extension?

14. Limit of proportionality? What is meant by this term? Label with a star the limit of proportionality on the rubber band and polythene strip

15. Hooke’s Law The extension of an elastic object is directly proportional to the force applied, provided that the limit of proportionality is not exceeded: Formula: F = k x e – F is the force in newtons, N – k is the spring constant in newtons per metre, N/m – e is the extension in metres, m

16. The spring constant The spring constant is the force per unit extension needed to extend the spring, assuming you do not exceed the limit of proportionality. The stiffer a spring is, the g_____ its spring constant.

17. Complete the example (grade C) A spring has a spring constant of 25 N/m. How much force is needed to extend the spring by 0.1m? F = k x e F =

18. Using bbc bitesize (grade C) Resaerch the equations and UNITs for each one and an example calculation: Momentum equation Work done equation Weight equation

19. Print out the handout as a revision tool