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 converted into kinetic energy while sliding down is dissipated. This energy is transformed mainly into thermal energy due to friction with the water and air resistance, and it may also generate sound energy. Thus, the energy does not disappear but is transferred to the surroundings.

To calculate the work done against the force of friction, the distance moved along the slope should be used. This distance represents the path over which the force of friction acts. The horizontal or vertical distances would not account for the work done due to the frictional force acting along the slope.

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

$m = 58 \text{ g} = 0.058 \text{ kg}$

The formula for kinetic energy (KE) is:

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

Substituting in the values:

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

Calculating this:

$KE = 0.029 \times 784 = 22.736 \text{ J}$

Therefore, the kinetic energy of the tennis ball is approximately 22.74 J.