Question

Analogue of mass in rotational motion is:

• A. Moment of inertia
• B. Angular momentum
• C. Gyration
• D. None of these

Answer 1

The correct option is A

Moment of inertia

Mass in translational motion:

1. The motion in which all points of a body move from one place to another at a uniform speed in the same direction is called translational motion.
2. The mass of a body is its tendency to resist motion. The higher the mass, the more it is difficult to move a body.
3. For instance, moving a rock of $1kg$ is easier than moving a rock of $10kg.$.

Moment of inertia in the rotational moment:

1. The motion in which an object moves in a circular path in a fixed orbit is called rotational motion.
2. Moment of inertia is the tendency of an object to resist angular motion. The higher the inertia, the more it is difficult to move a body.
3. Moment of inertia is directly proportional to the mass of the object and the square of the radius of its orbit.
4. For instance, it is difficult to move a door from its hinges because the radius is very small there.

Hence, the analogue of mass in rotational motion is the moment of inertia. Hence, option A is correct.