Question

A box is released from rest and allowed to slide down a ramp with friction. Which statement most accurately describes the energy transformations during this motion?
a) The box’s initial kinetic energy is transformed into potential energy.
b) The box’s initial potential energy and thermal energy is transformed into
kinetic energy.
c) The box’s initial kinetic energy is transformed into potential energy and
thermal energy.
d) The box’s initial potential energy is transformed into kinetic energy and
thermal energy.

Answer 1

Answer:

d) The box’s initial potential energy is transformed into kinetic energy and

thermal energy.

Explanation:

Let us analyze the situation first. Initially we have a box at rest placed at some height on a ramp. So, the three energies associated with the box will be:

Kinetic Energy = 0 (due to zero velocity)

Thermal Energy = 0 (due to not temperature change)

Potential Energy = Greater than zero value (due to height)

Now, when the box is released to slide down the ramp with friction, the energies become:

Kinetic Energy = Increasing (due to increase in velocity)

Thermal Energy = Increasing (due to increase in temperature, because of friction)

Potential Energy = Decreasing (due to decrease in height)

So, from Law of Conservation of Energy, we can write:

Loss of Potential Energy = Gain in Kinetic Energy + Gain in Thermal Energy

So, the correct option is:

d) The box’s initial potential energy is transformed into kinetic energy and  thermal energy.