This question is about energy changes - Edexcel - GCSE Physics - Question 6 - 2021 - Paper 1

As the person comes to rest after the end of the water slide, the gravitational potential energy that was converted to kinetic energy during the slide is dissipated.

1. Energy Transfer: The kinetic energy is transferred to the surroundings as heat due to friction with the water and air.
2. Overall Energy Change: The total mechanical energy decreases as the person stops moving, and some of that energy may also be converted to sound energy.

To calculate the work done against the force of friction, the distance along the slope should be used.

This is because work is defined as the force applied over a distance in the direction of that force. The slope distance provides the correct measure over which friction acts when moving the box up the slope.

First, convert the mass of the tennis ball from grams to kilograms:

$m = 58 ext{ g} = 0.058 ext{ kg}$

Using the kinetic energy formula:

$KE = \frac{1}{2} m v^2$

Substituting the values:

$KE = \frac{1}{2} \times 0.058 \text{ kg} \times (28 ext{ m/s})^2$

Calculating this gives:

$KE = \frac{1}{2} \times 0.058 \times 784$

$KE = 22.724 \text{ J}$