Question

Assuming no friction, how does the initial gravitational potential energy of
the marble on a downward slope compare to the final kinetic energy?

a) they are the same
b) the initial gravitational potential energy is greater than the final kinetic energy
c) the initial gravitational potential energy is less then the final kinetic energy

Answer 1

Answer:

a) They are the same.

Explanation:

Assuming no friction, there should be no energy transfer and thus the Law of Conservation of Energy says:

$PE=KE,\\mgh=\frac{1}{2}mv^2$

These types of problems also disregard any air resistance the surface of the object may cause. Therefore, no energy is transferred and from the Law of Conservation of Energy, $100\%$ of energy is preserved.