When one ball is raised, it acquires potential energy which is then transformed into kinetic energy once the ball is released.

In theory, the total energy should be conserved such that the balls continue in perpetual motion. However, over time, the balls stop moving. Why?

You can find results and justify them? you can test your hypothesis

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

The independent variable in this experiment is the angle at which the light from the ray box strikes the mirror.hope this .