Here's why:

* Mass in linear motion: Mass is a measure of an object's resistance to changes in linear motion (acceleration). A larger mass requires more force to accelerate.

* Moment of inertia in rotational motion: Moment of inertia is a measure of an object's resistance to changes in rotational motion (angular acceleration). A larger moment of inertia requires more torque to accelerate the object rotationally.

Key points:

* Formula: Moment of inertia (I) is calculated using the formula I = Σ(m_ir_i²), where m_i is the mass of each particle and r_i is its distance from the axis of rotation.

* Dependence on mass distribution: Moment of inertia is not just about the total mass of an object, but also how that mass is distributed around the axis of rotation. A more spread-out mass distribution results in a higher moment of inertia.

* Rotational kinetic energy: Just like linear kinetic energy depends on mass, rotational kinetic energy depends on moment of inertia: KE_rot = (1/2)Iω², where ω is the angular velocity.

Analogous relationships:

| Linear Motion | Rotational Motion |

|---|---|

| Mass (m) | Moment of inertia (I) |

| Force (F) | Torque (τ) |

| Linear acceleration (a) | Angular acceleration (α) |

| Linear velocity (v) | Angular velocity (ω) |

| Linear momentum (p = mv) | Angular momentum (L = Iω) |

Understanding the concept of moment of inertia is crucial for analyzing and understanding rotational motion in physics.