An electric car is travelling at a speed of 16.0 m/s - Edexcel - GCSE Physics Combined Science - Question 5 - 2023 - Paper 2

To find the time taken (t) for the battery to become discharged, we use the relationship between energy (E), power (P), and time:

$E = P \times t$

Rearranging for time, we have:

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

Here:

• E = total energy transferred = 126 MJ = 126 \times 10^6 J
• P = power = 17.5 kW = 17.5 \times 10^3 W

Substituting the values into the equation:

$t = \frac{126 \times 10^6}{17.5 \times 10^3}$

Calculating:

$t = \frac{126000000}{17500} \approx 7200 \text{ s}$

To convert seconds into hours, divide by 3600:

$t \approx \frac{7200}{3600} = 2 \text{ hours}$

Thus, the time taken for the battery to become discharged is 2 hours.