If you lift the front wheel of a poorly maintained bicycle off the ground and then start it spinning at 0.72 {\rm rev}/{\rm s}, friction in the bearings causes the wheel to stop

Question

in just 12 {\rm s}.

Answer 1

That may be true for this specific bicycle, but you have not asked a question.

You also need to explain the symbol
{\rm

Answer 2

If you lift the front wheel of a poorly maintained bicycle off the ground and then start it spinning at 0.72rev/s, friction in the bearings causes the wheel to stop
in just 12s.

Part A
If the moment of inertia of the wheel about its axle is 0.30kg\m2 , what is the magnitude of the frictional torque?

Answer 3

0.11 N*m