Momentum     BHS -> Mr. Stanbrough -> Physics -> Mechanics -> Momentum -> this page   As I'm sure you suspect, momentum in physics is different from "momentum" in sports on tv, as in "Yes, Chris, the Bengals really have momentum on this drive!". However, physics momentum is related to football momentum in that both concepts refer to how difficult it will be to stop something.

What makes an object difficult to stop? Its mass, for one thing. After all, mass measures the inertia of an object - how much the object resists accelerating. Certainly, more mass means more momentum - the momentum of an object is directly proportional to its mass. Twice the mass means twice the momentum. Momentum is not the same as mass, though. For one thing, an object that is not moving has no momentum, no matter how much mass it has.

Fast objects are also difficult to stop. Bullets have a very small mass, but you wouldn't want to try and stop one! More speed means more momentum - momentum is directly proportional to velocity. Twice the speed means twice the momentum.

Since the momentum of an object is directly proportional to both its mass and its velocity,

Momentum = (mass)(velocity) = mv

Momentum is a vector quantity. Its direction is the same as the direction of the object's velocity.

Calculating Momentum

Calculating the momentum of an object is usually easy and straightforward, just multiply the object's mass times its velocity.

Example:

A ball of mass 2 kg. is moving with a speed of 4 m/s. What is its momentum?

Solution: Momentum = (mass)(velocity) = (2 kg)(4 m/s) = 8 kg m/s     BHS -> Mr. Stanbrough -> Physics -> Mechanics -> Momentum -> this page
last update December 27, 2005 by JLStanbrough