Four students carry out an investigation to determine their powers when running up stairs - Edexcel - GCSE Physics Combined Science - Question 4 - 2022 - Paper 1

The unit for work done is the joule (J).

Using the formula for work done, we have:

$E = F \times d$

Where:

• E = 1960 J
• d = 4.0 m

Rearranging gives: $F = \frac{E}{d} = \frac{1960}{4.0} = 490 \text{ N}$

Therefore, the estimated weight is 490 N.

For student C, using the rearranged work formula:

Using the equation:

$E = F \times d$

We know:

• E = 2040 J
• F = 510 N
• d = 4.0 m

First, we calculate the time:

$ext{Power} = \frac{E}{t}$

Given the power is 425 W for student C:

$t = \frac{E}{P} = \frac{2040}{425} \approx 4.8 \text{ s}$

Thus, the time taken is approximately 4.8 s.

The average power can be found by calculating the total work done divided by the total time taken by all students:

Total work done is:

$E_{total} = 2200 + 1960 + 2040 = 6200 \text{ J}$

Total time taken is: $t_{total} = 5.0 + 4.5 + 4.8 = 14.3 \text{ s}$

Now calculating average power:

$P_{average} = \frac{E_{total}}{t_{total}} = \frac{6200}{14.3} \approx 433.6 \text{ W}$

Thus, the average power is approximately 433.6 W.

A significant source of error could be the estimation of the students' weight. This could be reduced by using a precise weighing scale to determine each student’s actual weight before the experiment.