Question: What is the work done by a torque of 5 N·m that rotates an object through an angle of 90 degrees?

Options:

1. 0.5 J
2. 1 J
3. 2.5 J
4. 5 J

Correct Answer: 2.5 J

Solution:

Work done by torque is W = τθ, where θ = π/2 rad. Thus, W = 5 N·m * (π/2) = 5 * 1.57 = 7.85 J.