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 kinetic energy acquired during the slide is transformed into other forms of energy. Primarily, this energy is dissipated as thermal energy due to friction with the surface of the slide and air resistance. Additionally, some energy may be transferred to the surrounding environment, such as through sound as the person impacts the water or the ground.

To calculate the work done against the force of friction, you should use the distance along the slope the box is pushed. This is important because frictional force acts parallel to the surface over which the box is moved, which in this case is represented by the distance along the inclined plane.

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

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

Now, using the kinetic energy formula:

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

Substituting the values:

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

Calculating this yields:

$KE = \frac{1}{2} \times 0.058 \times 784 \approx 22.736 \text{ J}$