Give the physical significance of moment of inertia. Explain the need of fly wheel in Engine

Explanation

### Step-by-Step Solution:

**Step 1: Understanding Moment of Inertia**
- The moment of inertia (I) is a measure of an object's resistance to changes in its rotational motion. It is analogous to mass in linear motion. The greater the moment of inertia, the more torque is needed to change the rotational speed of the object.

**Step 2: Physical Significance of Moment of Inertia**
- Moment of inertia plays a crucial role in rotational dynamics. It quantifies how mass is distributed relative to the axis of rotation. For example, if a body is at rest, it tends to remain at rest, and if it is rotating, it tends to keep rotating unless acted upon by an external torque. This property is similar to how mass resists changes in linear motion.

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