Figure 4 shows a sailing boat crossing an ocean - AQA - GCSE Physics Combined Science - Question 3 - 2021 - Paper 1

1. The generator can provide energy when there is no wind, ensuring continuous power availability.
2. Utilizing both the wind turbine and the fossil fuel generator allows for a more reliable energy supply.

One significant environmental impact of using fossil fuels is the emission of carbon dioxide (CO2), which contributes to global warming and the greenhouse effect.

To find the speed of the boat, we can use the formula for kinetic energy:

$KE = \frac{1}{2}mv^2$

Substituting the given values:

$81 000 J = \frac{1}{2} \times 8000 kg \times v^2$

Rearranging gives:

$v^2 = \frac{81 000 J}{0.5 \times 8000 kg} \Rightarrow v \approx 4.5 \, m/s$

To find the change in height ($\Delta h$), we can use the potential energy formula:

$PE = mgh$

Here, we have:

$19 600 J = 8000 kg \times 9.8 N/kg \times \Delta h$

Rearranging gives:

$\Delta h = \frac{19 600 J}{8000 kg \times 9.8 N/kg} \approx 0.25 \, m$