A student lifts a toy car from a bench and places the toy car at the top of a slope as shown in Figure 9 - Edexcel - GCSE Physics Combined Science - Question 5 - 2020 - Paper 1

To measure the speed of the toy car at the bottom of the slope, the student should conduct the following steps:

1. Measure the distance the toy car travels down the slope using a ruler.

2. Use a stopwatch to measure the time it takes for the toy car to reach the bottom.

3. Calculate the speed using the formula:

   $ext{Speed} = \frac{\text{Distance}}{\text{Time}}$

4. To enhance accuracy, the student could repeat the experiment multiple times and average the results.

The student must measure the following:

1. The vertical height of the slope (which relates to the potential energy).
2. The mass of the toy car (to calculate energy transformations).

The student could calculate the thermal energy transferred to the surroundings by utilizing the equation:

$\text{Original GPE} - \text{KE (at the bottom)} = \text{Energy transferred to surroundings}$

Where the original gravitational potential energy is calculated using:

$\text{GPE} = mgh$

and the kinetic energy at the bottom by:

$\text{KE} = \frac{1}{2}mv^2$

One method to reduce thermal energy transfer is to lubricate or oil the wheels of the toy car. This reduces friction between the wheels and the slope, which decreases the amount of energy that is converted into thermal energy during the descent. Additionally, making the slope surface smoother could further enhance the efficiency of the roll.