Answer:
A. <em>Loses PE and gains KE </em>
Explanation:
Statement is incomplete. Complete statement of problem is:
<em>1. An object from a certain height falls freely. Which of the following happens to PE and KE when the object is half on its way down? </em>
A. <em>Loses PE and gains KE </em>
B. <em>Gains PE and loses KE </em>
C. <em>Loses both PE and KE </em>
D. <em>Gains both PE and KE</em>
If we neglect the effects of any conservative force, the application of the Principle of Energy Conservation is reduced to a sum of gravitational potential () and translational kinetic energies, measured in joules. That is:
(Eq. 1)
Let assume that an object falls from a height with a speed of zero. By definitions of gravitational potential and translational kinetic energies the previous is expanded. If final height is the half of initial value, then:
(Eq. 1b)
In a nutshell, translational kinetic energy is increased at the expense of diminishing gravitational potential energy. The correct answer is A.