1. Elastic Potential Energy: Learning Goals
The student will describe the elastic potential energy of a spring or similar object in qualitative and quantitative terms and will investigate the transformation of gravitational potential to elastic potential.

2. Elastic Potential Energy
4C Physics

3. Hooke’s Law
The stretch or compression of an elastic device (e.g. a spring) is directly proportional to the applied force:

4. Hooke’s Law
The stretch or compression of an elastic device (e.g. a spring) is directly proportional to the applied force:

5. The spring constant
The constant k is called the spring constant or force constant. It has units of N/m
and is the slope of the line in a force-extension graph.

6. Example 1
A student stretches a spring 1.5 cm horizontally by applying a force of magnitude 0.18 N. Determine the force constant of the spring.

7. Example 1
A student stretches a spring 1.5 cm horizontally by applying a force of magnitude 0.18 N. Determine the force constant of the spring.

8. Example 1
A student stretches a spring 1.5 cm horizontally by applying a force of magnitude 0.18 N. Determine the force constant of the spring.

9. Example 1
A student stretches a spring 1.5 cm horizontally by applying a force of magnitude 0.18 N. Determine the force constant of the spring.

10. Example 1
A student stretches a spring 1.5 cm horizontally by applying a force of magnitude 0.18 N. Determine the force constant of the spring.

11. Elastic Potential Energy
The force stretching or compressing a spring is doing work on a spring, increasing its elastic potential energy. Note that this force is not constant but increases linearly from 0 to kx. The average force on the spring is ½kx.

12. Elastic Potential Energy
The force stretching or compressing a spring is doing work on a spring, increasing its elastic potential energy. Note that this force is not constant but increases linearly from 0 to kx. The average force on the spring is ½kx.

13. Example 2
An apple of mass 0.10 kg is suspended from a vertical spring with spring constant 9.6 N/m. How much elastic potential energy is stored in the spring if the apple stretches the spring 20.4 cm?

14. Example 2
An apple of mass 0.10 kg is suspended from a vertical spring with spring constant 9.6 N/m. How much elastic potential energy is stored in the spring if the apple stretches the spring 20.4 cm?

15. Example 2
An apple of mass 0.10 kg is suspended from a vertical spring with spring constant 9.6 N/m. How much elastic potential energy is stored in the spring if the apple stretches the spring 20.4 cm?

16. Example 2 Follow-Up
How much gravitational potential energy did the apple lose?

17. Example 2 Follow-Up
How much gravitational potential energy did the apple lose?

18. Example 2 Follow-Up
How much gravitational potential energy did the apple lose?

19. Example 2 Follow-Up
How much gravitational potential energy did the apple lose?

20. The ideal spring
An ideal spring is one that obeys Hooke’s Law – within compression/stretching limits. Beyond those limits the spring may deform.

21. The ideal spring
An ideal spring is one that obeys Hooke’s Law – within compression/stretching limits. Beyond those limits the spring may deform.
Be gentle with my springs!

22. Kinetic Energy: More Practice

23. Kinetic Energy: More Practice

24. Kinetic Energy: More Practice

25. Kinetic Energy: More Practice

26. Kinetic Energy: More Practice

27. Kinetic Energy: More Practice