A student carries out an experiment to investigate friction between a puck and the surface of a table - Scottish Highers Physics - Question 2 - 2022

We can use Newton's second law, which states that:

$F = ma$

Given:

• Mass of puck, $m = 0.350 \, \text{kg}$
• Average acceleration, $a = -0.1414 \, \text{ms}^{-2}$

Substituting the values:

$F = 0.350 \, \text{kg} \times (-0.1414 \, \text{ms}^{-2})$

Calculating the force:

$F = -0.04949 \, \text{N} \approx -0.049 \, \text{N}$

The magnitude of the force is therefore:

$|F| = 0.049 \, \text{N}$

The statement is incorrect because the mass measurement does not have the largest percentage uncertainty. The percentage uncertainty is calculated using the formula:

$\text{Percentage Uncertainty} = \left( \frac{\text{Absolute Uncertainty}}{\text{Measurement}} \right) \times 100$

For the mass of 0.350 kg with an absolute uncertainty of ±0.001 kg, the percentage uncertainty is:

$\left( \frac{0.001}{0.350} \right) \times 100 \approx 0.29\%$

For the initial speed of 0.78 m/s with an absolute uncertainty of ±0.01 m/s, the percentage uncertainty is:

$\left( \frac{0.01}{0.78} \right) \times 100 \approx 1.28\%$

Since the initial speed has a higher percentage uncertainty, it is more uncertain than the mass measurement.