Question Detail
Question
The shear modulus disk stopping problem: A solid circular disk of radius 0.6 m and mass 90 kg is rotating at 460 rev/min. What force applied tangentially will stop it in 20 s?
Correct Answer
Option D is the correct answer.
Detailed Explanation
ω = 48.17 rad/s. α = −2.41 rad/s². I = ½mr² = 16.2. τ = Iα = 39.1 N·m. F = τ/r = 39.1/0.6 ≈ 65 N.
Hint
Use τ = Iα then F = τ/r.