When a pole vaulter reaches the top of her vault, how does her potential energy compare to her kinetic energy?
a
The kinetic energy and potential energy are the same.
b
The kinetic energy is greater than the potential energy.
c
The kinetic energy is less than the potential energy.
d
The kinetic energy is twice the amount of potential energy.
c. The kinetic energy is less than the potential energy.
Explanation: When a pole vaulter reaches the top of her vault, she is momentarily stationary at the peak of her trajectory before she starts to descend. At this highest point, all of the kinetic energy she had during her run-up and vault has been converted into gravitational potential energy. Since she is not moving at the top (her velocity is zero), her kinetic energy is zero. Therefore, her potential energy is at its maximum, and her kinetic energy is less than her potential energy (in fact, it's zero at that exact moment).