5. (a) Which of these is the equation for work done? A work done = force ÷ distance moved in direction of force B work done = force × distance moved in direction of force C work done = force ÷ distance moved at right angles to direction of force D work done = force × distance moved at right angles to direction of force (b) A ball has a mass of 0.046 kg - Edexcel - GCSE Physics Combined Science - Question 5 - 2019 - Paper 1

To calculate the change in gravitational potential energy (GPE), we use the formula:

$\Delta GPE = m \times g \times \Delta h$

where:

• mass (m) = 0.046 kg
• gravitational acceleration (g) ≈ 9.81 m/s²
• height change (\Delta h) = 2.05 m

Substituting the values:

$\Delta GPE = 0.046 \times 9.81 \times 2.05$

Calculating this gives:

$\Delta GPE ≈ 0.0888 \, J$ (this can be rounded to 0.09 J).

The kinetic energy (KE) can be calculated using the formula:

$KE = \frac{1}{2} m v^2$

where:

• mass (m) = 0.046 kg
• velocity (v) = 3.5 m/s.

Substituting the values:

$KE = \frac{1}{2} \times 0.046 \times (3.5)^2$

Calculating this:

$KE = 0.5 \times 0.046 \times 12.25 ≈ 0.282 \text{ J}$ (rounded to 0.28 J).

From Figure 7, we can observe the height of the ball after the first bounce and estimate it to be about 0.9 m.

The ball does not bounce back to its starting height of 2.05 m because it loses energy during the bounce. This loss can occur due to:

• energy being dissipated to the surroundings (heat, sound)
• the ground absorbing some energy
• the bounce being inelastic, where not all kinetic energy converts back to potential energy.

As the bounce number increases, the maximum height reached after each bounce decreases, indicating a negative correlation. The relationship appears to be non-linear, as the height drops significantly with the initial bounces and then stabilizes. This trend suggests that each successive bounce does not recover the same amount of height as the previous one.