# Momentum

Written by Jerry Ratzlaff on . Posted in Classical Mechanics Momentum, abbreviated as p, also called linear motion or translational momentum, of an object is the amount of mass in motion.  Momentum is a vector quantity having magnitude and direction, some of these include acceleration, displacement, drag, force, lift, thrust, torque, velocity, and weight.  The change in momentum is called impulse.

Practically, momentum is the measure of inertia for objects in motion.  It helps quantify how difficult it is to stop something.  It is commonly used in a derivation of Newton's First Law where there is no change in momentum if there are no outside forces acting on a system.

## Momentum Types

• Inertia  -  Inertia is a body’s resistance to change in speed and is related to its mass and the distance of that mass from the axis of rotation.
• Linear Momentum  -  If the net external force acting on a system of bodies is zero, then the momentum of the system remains constant.

## Momentum formula

 $$\large{ p = m \; v }$$

### Where:

 Units English Metric $$\large{ p }$$ = momentum $$\large{\frac{lbm-ft}{sec}}$$ $$\large{\frac{kg-m}{s}}$$ $$\large{ m }$$ = mass $$\large{lbm}$$ $$\large{kg}$$ $$\large{ v }$$ = velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ 