Question

A bicycle and its rider have a total mass of 70.0 kg. Each of its wheels can be modeled as a thin hoop with mass 1.26 kg and diameter of 70.0 cm. When the brakes are applied, two brake pads squeeze the rims of each wheel. Assume that the four brake pads exert normal forces on the wheels that are equal and constant in magnitude. The coefficient of kinetic friction between a brake pad and a wheel is 0.900. The bicycle is moving on level ground with a linear speed of 7.50 m/s. When the brakes are applied, the bicycle is stopped in 5.30 s.

Find the magnitude of the net torque on each wheel about its axle.

Answer 1

Find the initial angular speed using linear speed and radius of the wheel. Find angular acceleration using equation of rotational kinematics and use moment of inertia and angular acceleration magnitude to find the magnitude net torque as shown below