Question: A torque τ is applied to a rigid body with moment of inertia I. If the body starts from rest, what is the angular displacement θ after time t?

Options:

1. (1/2)(τ/I)t^2
2. (τ/I)t^2
3. (1/2)(I/τ)t^2
4. (I/τ)t^2

Correct Answer: (1/2)(τ/I)t^2

Solution:

Using the equation of motion for rotation, θ = (1/2)αt^2, where α = τ/I, thus θ = (1/2)(τ/I)t^2.