Question Detail
Question
A flywheel starts from rest and accelerates uniformly. After 10 seconds, it has completed 20 revolutions. What is its angular acceleration?
Correct Answer
Option C is the correct answer.
Detailed Explanation
θ = 20 rev = 20 * 2π = 40π rad. ωi = 0. Using θ = ωit + (1/2)αt², we get 40π = 0 + (1/2)α(10)² = 50α. Therefore, α = (40π)/50 = 0.8π rad/s².
Hint
First convert the angular displacement from revolutions to radians. Then use the rotational equation of motion that relates displacement, initial velocity, time, and acceleration.