Question 6

A flywheel-powered passenger shuttle is used on a public transit route. When the shuttle is at a stop, its flywheel is accelerated to a high rotational speed to store energy.

The total mass of the loaded shuttle is $1.25 \times 10^4 \text{ kg}$ .
Between stops A and B, the track is inclined at a constant $6.0∘6.0^\circ$ to the horizontal, and the distance along the incline between these stops is $\text{ m}$ .
The total resistive force opposing the motion is constant at $\text{ kN}$ .
The flywheel has a moment of inertia of $\text{ kg m}^2$ .

Calculate the minimum angular speed of the flywheel when the shuttle leaves stop A so that the shuttle reaches stop B using only the energy stored in the flywheel. (Use $\text{ m s}^{-2}$ )

Between stops C and D, the shuttle travels downhill. Suggest two advantages of keeping the flywheel connected to the driving wheels when the shuttle travels downhill.

To use the same shuttle on a different route with longer distances between stops, the flywheel system must be modified to store more energy. Discuss the design features of the flywheel that will enable it to store more energy without increasing the overall mass of the shuttle.