# Momentum Definition [Class-12 Physics]

Momentum Definition: Momentum of a moving body or particle is mass x velocity. This is a central concept of physics, and is very useful in study of stellar bodies to sub-atomic particles. Momentum are of two types: Linear Momentum and Angular Momentum.

## Momentum Definition – The two types

 Linear Momentum Angular Momentum Definition mass x Linear Velocity Moment of Inertia x Angular Velocity Equation $\vec P = m \vec V$ $\vec L = I \vec \omega$ Units (SI) N.s N.m.s/rad Units (MKS) kg.m/s kg.m²/s/rad Dimensions $\left[ MLT^{-1} \right]$ $\left[ ML^{2}T^{-1} \right]$

## Defining Linear Momentum

Linear Momentum (P) is the measure of the effort required to stop a moving body, moving in a straight line. More the linear momentum, more the effort is required to stop the object, or alternatively, if the effort is limited, then more is the time that effort must be applied to stop the object. For example, the effort required to stop a bicycle is small in comparison to stopping a train. The train has more momentum by virtue of its velocity or mass or both.

## Defining Angular Momentum

Angular Momentum (L) is the measure of the effort required to stop a spinning body. A spinning top can be stopped easily as compared to stopping a planet rotating about its axis! The more the angular momentum, which is due to combined effect of Moment of Inertia (I) and Angular velocity, more is the effort required (Stopping Torque) to bring the spinning body to rest.