# Quantity of motion (momentum). Law of conservation

## Do you want to deepen your knowledge about the concept of quantity of motion?

The online quantity of motion simulations on this page will help you to deepen your understanding of this important physics concept and to study and understand the law of conservation of quantity of motion.

The online quantity of motion simulations on this page will help you to deepen your understanding of this important physics concept and to study and understand the law of conservation of quantity of motion.

The quantity of motion, also known as momentum, is a physical vector quantity used to describe the motion of an object in relation to its mass and velocity. The concept of quantity of motion is fundamental in physics and is calculated by multiplying the mass (m) of the object by its velocity (v).

Quantity of motion (p) = mass (m) * velocity (v)

A direct consequence of Newton’s third law (action – reaction) is the law of conservation of the quantity of motion which states that the total quantity of motion of an isolated system remains constant unless acted upon by external forces. Therefore, in an isolated system, if there are no external forces acting on the objects, the total amount of motion before an event will be equal to the total amount of motion after that event.

The law of conservation of the quantity of motion is especially useful in situations where several objects interact, such as collisions or explosions. In these cases, equations based on the conservation of the quantity of motion can be used to determine the final velocities of the objects after the event.

Below are several simulations and other educational resources, which can also serve as very illustrative examples. In addition, a selection of books and courses is included to help you broaden your knowledge of this subject.

## Quantity of Motion (Momentum)

The quantity of motion (momentum) of an object is the product of mass times velocity. Is the amount of motion a scalar or vector quantity?

## Water rocket

A water rocket contains water under high pressure. When the water is released, it is ejected downward and the rocket is propelled upward. Can you explain why this happens?
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