Study the scenario.

An ice block in motion begins to slide up an icy hill. The system consists of the block, the hill, and the Earth. (There is no friction.)

Which choice best describes the changes in kinetic and potential energy?

The kinetic energy decreases as the block moves up the hill because it slows down. The potential energy increases because the block’s height relative to its starting position increases. The total energy remains constant.

The kinetic energy increases as the block moves up the hill because it speeds up. The potential energy increases because the block’s height relative to its starting position increases. The total energy increases.

The kinetic energy remains constant as the block moves up the hill because its speed remains constant. The potential energy remains constant because the block remains on the ground the entire time. The total energy remains constant.

The kinetic energy remains constant as the block moves up the hill because its speed remains constant. The potential energy increases because the block’s height relative to its starting position increases. The total energy increases.

As the block moves up the hill, kinetic energy is converted into gravitational potential energy. As a result, the block slows down as its height increases.

Thus, kinetic energy in the block would decrease. Gravitational Potential energy in this system would increase.

The mechanical energy of the block is the sum of its kinetic and potential energy. If gravity and normal force from the slope are the only forces on the block (i.e., no friction,) mechanical energy on the block would be conserved. In other words, as the block moves up the slope, total energy in this system would stay the same under the assumptions.