Question Detail
Question
A flywheel of radius 1.2 m and moment of inertia 12.5 kg m² starts from rest and attains an angular speed of 10 rad/s in 5 seconds with uniform angular acceleration. What is the magnitude of the constant torque acting on the flywheel?
Correct Answer
Option B is the correct answer.
Detailed Explanation
First, calculate the angular acceleration α = Δω / t = (10 rad/s) / 5 s = 2 rad/s². Torque τ is related to moment of inertia I and angular acceleration α by τ = I α. Substituting I = 12.5 kg m² and α = 2 rad/s² gives τ = 12.5 kg m² × 2 rad/s² = 25 Nm.
Hint
Use the rotational form of Newton's second law, τ = I α. You must first determine α from the given kinematic data.