Unit VII Elastic Potential Energy WS
Problems 1 & 2: Suppose in the lab one group found that the spring had a spring constant
of 10 N/m. Draw a graph of force vs. deformation for this spring.
1. Graphically and mathematically determine the amount of energy stored while
stretching the spring 1 m.
2. Graphically and mathematically determine the total amount of energy if the spring
were stretched an additional 1 m to a total deformation of 2 m.
Problems 3, 4 & 5: Suppose two springs were tested by two different groups. Group A’s
spring stretched 2m under a force of 16N and group B’s spring stretched 3m with an
applied force of 15 N.
3. For each spring determine the spring constant. Which spring is “stronger”?
4. For each spring, compare
a. the amount of force required to stretch the spring 3.0 m.
b. the Eel stored in each spring when stretched 3.0 m.
5. Determine the amount each spring needs to be stretched in order to store 50 J of
energy.
Problems 6 & 7
6. A spring with a spring constant of 10 N/m has a block attached. You pull the block
0.30 m horizontally to the right, and hold the block motionless. What force does the
spring exert on the block? Sketch a quantitative force diagram for the mass as you
hold it still. (Assume a frictionless surface.)
7. A spring has a spring constant of 20 N/m. The coefficient of static friction between
the 1 kg box and the surface is 0.40. (Now there is friction.)
a. The box is pulled to the right and then released. Draw a force diagram for the
box when the spring is stretched, yet the box is stationary.
b. What is the maximum distance that the spring can be stretched from
equilibrium before the box begins to slide back?