Question Detail
Question
A wheel whose rotational inertia is 10 kg·m² starts from rest and accelerates under a constant torque of 3.0 Nm for 8.0 seconds. What is the wheel's rotational kinetic energy at the end of the 8 seconds?
Correct Answer
Option A is the correct answer.
Detailed Explanation
α = τ/I = 3/10 = 0.3 rad/s². ω = αt = 0.3 × 8 = 2.4 rad/s. KE_rot = ½Iω² = ½ × 10 × (2.4)² = 5 × 5.76 = 28.8 J.
Hint
KE_rot = ½Iω², ω = αt.