If you've ever kicked a ball, hit a punching bag, or played sports that involved any kind of ball, you have been using the concept of impulse without even knowing it. So what exactly is impulse, and what does it have to do with any of those situations?
Before we can define impulse, we need to talk about the concept of momentum. Momentum is a measure of strength and a measure of how difficult it is to stop an object. An object that is not moving has zero momentum. A slow-moving, large object has a large momentum. A fast-moving, small object also has a large momentum. For example, if a ping-pong ball and a bowling ball have the same velocity, then the bowling ball has a greater momentum because it is more massive than the ping-pong ball.
This is the formula for momentum:
In this formula, Momentum (p) equals Mass (m) times Velocity (v). Momentum is a vector which is equal to the product of mass and velocity (which is also a vector).
But how is momentum related to impulse? When a force acts on an object for a short amount of time, impulseis the measure of how much the force changes the momentum of an object.
The formula for impulse looks like this:
Because impulse is a measure of how much the momentum changes as a result of force acting on it for a period of time, an alternative formula for impulse looks like this:
This formula relates impulse to the change in the momentum of the object. Impulse has two different units, either kilogram times meters per second (kg m/s) or Newton times seconds (Ns).
