Linear momentum

Definition

Linear momentum is the product of an object's mass and its velocity. It is a vector quantity, possessing both magnitude and direction.

5 Must Know Facts For Your Next Test

1. The formula for linear momentum is $\mathbf{p} = m\mathbf{v}$, where $m$ is mass and $\mathbf{v}$ is velocity.
2. Linear momentum is conserved in isolated systems with no external forces.
3. The unit of linear momentum in the International System (SI) is kilogram meter per second (kg·m/s).
4. Impulse, defined as the change in momentum, equals the force applied multiplied by the time interval over which it acts: $\mathbf{J} = \Delta \mathbf{p} = \mathbf{F}\Delta t$.
5. In collisions, whether elastic or inelastic, total linear momentum before and after the collision remains constant.

Review Questions

• What is the formula for calculating linear momentum?
• How does linear momentum behave in an isolated system with no external forces?
• What physical quantity has units of kg·m/s?

Related terms

Impulse:

Impulse is the change in an object's momentum due to a force applied over a period of time. It can be calculated using $\mathbf{J} = \Delta \mathbf{p} = \mathbf{F}\Delta t$.

Conservation of Momentum:

A principle stating that the total linear momentum of a closed system remains constant provided no external forces are acting on it.

Elastic Collision:

A type of collision where both kinetic energy and linear momentum are conserved.