⚛️ Physics · System of Particles and Rotational Motion · NEET & JEE

The kinetic energy of a rolling object can be written as (1/2)mv²(1 + k²/R²) where k is radius of gyration. For a ring, k²/R² = 1. So the KE is:

Answer: mv².

A mv²
B (1/2)mv²
C (3/4)mv²
D (7/10)mv²

Correct answer: A. mv²

Explanation: KE = (1/2)mv²(1 + 1) = mv². For a ring, half is translational and half is rotational.

Torque about axis O equals the force F multiplied by the perpendicular distance r⊥ from the axis to the line of action of the force, producing rotation.

Concept context

Moment of inertia, torque, angular momentum, rolling motion. Very high JEE weightage.

Read the full System of Particles and Rotational Motion notes →

The kinetic energy of a rolling object can be written as (1/2)mv²(1 + k²/R²) where k is radius of gyration. For a ring, k²/R² = 1. So the KE is:

Concept context

More System of Particles and Rotational Motion questions