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 calculate the estimated weight of student B, use the formula for work done:

$E = F imes d$

Where:

• Work done (E) = 1960 J
• Distance (d) = 4.5 m

Rearranging for weight (F), we have:

$F = \frac{E}{d} = \frac{1960}{4.5} \approx 436.0 \, \text{N}$

To find the time taken by student C, we use the formula:

$E = F \times d$

Where:

• Work done (E) = 2040 J
• Weight (F) = 510 N

Rearranging gives us:

$t = \frac{E}{F} = \frac{2040}{510} \approx 4.0 \, \text{s}$

Average power (P) can be calculated using:

$P = \frac{E}{t}$

For student A:

• Work done = 2200 J, Time taken = 5 s
• Power = \frac{2200}{5} = 440 , \text{W}

For student B:

• Work done = 1960 J, Time taken = 4.5 s
• Power = \frac{1960}{4.5} \approx 436.0 , \text{W}

For student C:

• Work done = 2040 J, Time taken = 4.0 s
• Power = \frac{2040}{4.0} = 510.0 , \text{W}

Average power = \frac{440 + 436 + 510}{3} = \frac{1386}{3} \approx 462 , \text{W}.

A significant source of error could be the estimation of the students' weights, as it may not be accurate. This error can be reduced by using a calibrated weighing scale to measure the actual weight accurately.