Calculate the minimum angular speed of the flywheel when the tram leaves stop A so that the tram reaches stop B using only energy stored in the flywheel - AQA - A-Level Physics - Question 2 - 2022 - Paper 6

The energy stored in the flywheel can be related to its angular speed. For a solid disc, the energy stored is given by:

$E = \frac{1}{2} I \omega^2$

Where:

• $I$ is the moment of inertia (62.5 kg m²)
• $\omega$ is the angular speed in rad/s.

Setting this equal to the work done:

$\frac{1}{2} \times 62.5 \times \omega^2 = 590,000$

Rearranging the formula gives:

$\omega^2 = \frac{2 \times 590,000}{62.5}$

Calculating this yields:

$\omega^2 = 18,880 \\ \omega = \sqrt{18,880} \approx 137.23 \text{ rad/s}.$

Thus, the minimum angular speed of the flywheel is approximately 137.23 rad/s.