You are holding the axle of a bicycle wheel with radius

35.0 cm and mass 1.00 kg. You get the wheel spinning at a rate of

75.0 rpm and then stop it by pressing the tire against the pavement.

You notice that it takes 1.20 s for the wheel to come to a

complete stop. What is the angular acceleration of the wheel?

The angular acceleration of the wheel is - 6.54 rad/s²

Explanation:

We'll use the equations of motion for this.

w = 2πf

f = 75 rpm = 1.25 rps = 1.25 rev/s

w₀ = initial angular velocity = 2π * 1.25 = 7.85 rad/s

w = final angular velocity = 0 rad/s

t = 1.2 s

α = ?

w = w₀ + αt

0 = 7.85 + 1.2α

α = 7.85/1.2 = - 6.54 rad/s²