Question

The SI unit of rotational inertia is
1. rad/s
2. N-m
3. m s^-2
4. kg m²

Answer 1

Correct Answer - Option 4 : kg m²

The correct answer is option 4) i.e. kg m2

CONCEPT:

• Rotational inertia: It is the measure of the resistance offered by a body to angular acceleration about a given axis. Hence, this is a property of objects that can be rotated.
  • Rotational inertia is the equivalent of mass in linear mechanics. It depends on the mass and distribution of mass of the object.
  • The rotational inertia is commonly called the moment of inertia.

The moment of inertia of any object rotating at radius rr from the axis of rotation is given by:

​I = mr²

Where I is the moment of inertia and m is the mass of the object.

EXPLANATION:

Moment of inertia, I = mr²​

• The SI units of mass m and radius r are kg and m respectively. Hence, the SI unit of rotational inertia is kg m2.