## Saturday, March 4, 2017

### Linear Momentum and Conservation of Momentum Video Lesson

Linear momentum is a physical quantity that explains about the transfer of kinetic energy of one body with another when there is a collision with other body. It is mathematically defined as the product of mass and velocity of the body. If momentum is more, it transfer kinetic energy to other body more and vice versa. Momentum is a vector quantity and its direction is similar to the direction of velocity.

Linear momentum is a physical quantity that explains the translatory motion. We can define Newton's second law in terms of linear momentum. As per the law, force is defined as the rate of change of linear momentum. Momentum is a physical quantity that gives clarity regarding the ability of transfer of kinetic energy. We can also find the relation between linear momentum and kinetic energy and it is explained in the video lesson below.

Change of linear momentum

When a rigid body of constant mass changes its velocity, its linear velocity also changes. When a body either change its magnitude or direction of the velocity of the vector or both of them, then there is a change in the linear momentum. We can find the change in the linear momentum of a body as the change in the final linear momentum  of the body to its initial linear momentum in a given time. If the body is moving with a constant velocity, then there is no change in the momentum. We can find the change in the momentum in different cases and we can also find the direction.

We shall consider the component of the momentum that is actually changing and if any component of the momentum is not changing, then we need not consider it. Some simple cases of change in momentum is explained in the video lesson below.

Conservation of Linear momentum

Linear momentum for a body is conserved when no external force is acting on the body. Proving this is very simple. We have defined force as the rate of change of momentum. When applied force is zero, rate of change in momentum is zero and it means momentum is not changing with time. Thus linear momentum remains constant when no external force is acting on a body. It is explained in  the video lesson below.

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