Rotational Motion for JEE

The rotational analogue of force is called ____.

• torque
• momentum
• inertia
• impulse

What is the SI unit of torque?

• N·m
• J·s
• N/m
• kg·m²

Moment of inertia of a solid sphere about a diameter is:

• ML²/12
• MR²
• (1/2)MR²
• (2/5)MR²

I of a thin rod (mass M, length L) about its centre is:

• (1/2)MR²
• ML²/3
• MR²
• ML²/12

The ____ theorem states I = I_cm + Md².

• parallel-axis
• impulse-momentum
• work-energy
• perpendicular-axis

The perpendicular-axis theorem is valid only for flat laminar objects.

• True
• False

Newton's second law for rotation is written τ = ____.

• Iα
• (1/2)Iω²
• Iω
• mv

Angular momentum of a rigid body equals:

• (1/2)Iω²
• Iα
• Iω
• mvR

Angular momentum is conserved when net external torque is zero.

• True
• False

A skater pulling in arms spins slower because I increases.

• True
• False

Rotational kinetic energy is given by ____.

• Iω
• (1/2)Mv²
• (1/2)Iω²
• (1/2)Iα

The rolling condition links v and ω as:

• v = ω²R
• v = ω/R
• v = ωR
• v = R/ω

Rolling down an incline, which reaches the bottom first?

• Solid sphere
• Hollow cylinder
• Ring
• Solid cylinder

In ideal rolling, friction does no work because the contact point is at rest.

• True
• False

Moment of inertia of a solid disc about its central axis is:

• (2/5)MR²
• (1/2)MR²
• MR²
• ML²/3