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

1. Sometimes there is no wind, but the battery can still be charged using the generator.

2. When there is wind, less fuel is burned, resulting in reduced fuel costs.

One environmental impact of using fossil fuels to generate electricity is that it releases carbon dioxide, which increases global warming.

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

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

Substituting the known values: $81 \ 000 = \frac{1}{2} \times 8000 \times v^2$

Rearranging gives: $v^2 = \frac{81 \ 000 \times 2}{8000}$

$v = \sqrt{\frac{162 \ 000}{8000}}\approx 4.5 \text{ m/s}$

To calculate the change in height, we can use the formula for gravitational potential energy:

$PE = mgh$

Where:

• PE = change in potential energy = 19 600 J
• m = mass of the boat = 8000 kg
• g = gravitational field strength = 9.8 N/kg

Rearranging gives: $h = \frac{PE}{mg} = \frac{19600}{8000 \times 9.8} \approx 0.25 m$