Question Detail
Question
A wheel of radius 60 cm has a moment of inertia of 5 kg·m². A constant force of 60 N is applied tangentially to the rim. What is the power developed by this force after the wheel has been rotating for 4 seconds, starting from rest?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Power P = τω. The torque τ is constant. The angular velocity ω is not constant; it increases linearly with time from rest because a constant torque produces a constant angular acceleration (α = τ/I). Therefore, as ω increases, power P = τω also increases linearly with time.
Hint
Consider how angular velocity changes when a constant torque is applied to a wheel starting from rest.