1. Elastic potential energy (D. EEl)
In this situation, the spring is compressed with the toy on top of it. The toy is stationary, so it does not have kinetic energy. However, the spring is compressed, so it does have elastic potential energy, given by:
where k is the spring constant and x is the compression of the spring.
2. Gravitational potential energy (C. Eg)
In this situation, the spring has been released, so it returns to its natural position, so its elastic potential energy is zero. The toy is also stationary, since it is at its top position, where its velocity is zero, so its kinetic energy is also zero. However, the toy is now at a certain height h above the spring, so it has gravitational potential energy given by:
where m is the mass of the toy and g is the gravitational acceleration.
3. Gravitational potential and kinetic energy (A. Eg and EK)
In this situation, the toy is falling: so, it is moving with a certain speed v, so it has kinetic energy given by
Also, since it is at a certain height above the spring, it still has some gravitational potential energy, as in the previous point.
4. Gravitational potential energy (C. Eg)
The jumper is standing on the bridge, so it has gravitational potential energy given by its height h above the ground:
where m is the mass of the jumper.
5. This exercise has the same text of the previous one.