Law of Conservation of Momentum

Definition

The Law of Conservation of Momentum states that the total linear momentum of a closed system remains constant if no external forces are acting on it. This principle is fundamental in analyzing collisions and interactions in mechanics.

5 Must Know Facts For Your Next Test

1. Momentum is a vector quantity, meaning it has both magnitude and direction.
2. In an elastic collision, both momentum and kinetic energy are conserved.
3. In an inelastic collision, momentum is conserved but kinetic energy is not.
4. The formula for linear momentum is $p = mv$, where $p$ is momentum, $m$ is mass, and $v$ is velocity.
5. The principle applies to isolated systems where the net external force is zero.

Review Questions

• What does it mean for a system to be 'closed' or 'isolated' in the context of momentum conservation?
• How does the conservation of momentum differ between elastic and inelastic collisions?
• If two objects collide and stick together, how do you calculate their final velocity using the conservation of momentum?

Related terms

Linear Momentum:

A measure of an object's motion given by the product of its mass and velocity ($p = mv$).

Elastic Collision:

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

Inelastic Collision:

A type of collision where momentum is conserved but kinetic energy is not; objects may stick together post-collision.