Chapter 6, Problem 14Q

What happens to the gravitational potential energy when water at the top of a waterfall falls to the pool below?

To determine

What happens to the gravitational potential energy when water at the top of a waterfall falls to the pool below?

Answer to Problem 14Q

Solution:

The gravitational potential energy$\left(U_g\right)$ is transformed into kinetic energy$\left(K\right)$

and then that energy is transferred through collisions into thermal energy.

Explanation of Solution

Given:

Gravitational potential energy at the top of a waterfall and in the pool below.

At the top of the waterfall, the energy is completely gravitational potential$\left(U_g\right)$, as the water descends the gravitational potential energy$\left(U_g\right)$ is transformed into kinetic energy$\left(K\right)$

. At the instant when the water collides with the pool below the kinetic energy$\left(K\right)$

of the falling water is transferred to the water molecules of the pool through collisions, thermal energy is produced due to friction at the level of the water molecules in the pool.