The physical quantity which is produced by the combination of mass and velocity of a moving body is the momentum. Momentum depends on the mass and velocity of the body. Think about a loaded truck and a private car. You have to stop both the cars within the same distance. Which car needs hard brake to stop? The answer is tuck. Though the truck and the car are moving with the same speed, the truck possesses that physical quantity which is more is its momentum.

It is a measure of how difficult it is to stop something that is moving. Momentum is related to the force. This relation is obtained quantitatively in Newton’s second law of motion.

Momentum is the product of the mass and velocity of a moving body.

Let, the mass of a body = m

Velocity = v

**Momentum = mv ….. …… (1)**

It is a vector quantity. Its direction is in the direction of velocity. It is observed from equation (1) that the momentum of a body will be large if the body has a large mass and moving faster.

**Unit:** the unit of momentum is, unit of mass x unit of velocity, i.e. kg x ms^{-1} or kg ms^{-1} . If a body of 1 kg moves with a velocity of l ms^{-1}, its momentum will be 1 kg ms^{-1}.

**Dimension: The dimension of momentum: [p] = MLT ^{-1}.**