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 joules (J).

To find the weight for student B, we will use the formula for work done:
$E = F imes d$
Given that work done (E) is 1960 J and the distance (d) is 4.0 m, we rearrange the formula to find weight (F):
$F = \frac{E}{d} = \frac{1960}{4.0} = 490 \, \text{N}$
So, the estimated weight for student B is 490 N.

Using the work done and estimated weight for student C, we can find the time taken.
We use the formula:
$E = F \times d$
Here, E is 2040 J and the weight (F) is 510 N.
We can rearrange it to find distance (d):
$d = \frac{E}{F} = \frac{2040}{510} = 4 \, \text{m}$
Now to find the time (t) taken using the formula:
$P = \frac{E}{t}$
Where P is the power, which for student C is calculated as:
$P = \frac{2040}{t}$
As power can be derived from weight and time taken (using weight of 510 N):
Thus, we find that when the equation is solved for time, the time taken for student C is approximately 4.0 s.

To calculate the average power of the students, sum the power calculated for each student and divide by the number of students:
Average Power = ( \frac{440 + 436 + 425}{3} )
Average Power = ( \frac{1301}{3} \approx 433.67 ) W.
Thus, the average power of the students is approximately 434 W.

A significant source of error could be the estimation of the students' weights.
This error can be reduced by using a scale to measure the actual weight of each student instead of relying on their estimation.