Difference Between Momentum and Impulse

Momentum vs Impulse

Momentum is a property of a moving body and describes the force that is required to stop a moving body. When we say that a particular team has momentum at the moment, we mean to say that the team is on a roll and hard to be stopped by other teams in the tournament. Any object having momentum needs a force against it, and this force also needs to be applied for some time to stop the body. More the momentum, harder is it to stop a body. So it is clear that a moving body with a momentum can be stopped if a particular force is applied against it for some time.

According to Newton’s 2nd law of motion, Force is the product of mass and the acceleration of a body. Now acceleration is rate of change of velocity, so we can say that

F = m X a

= m X v1 -v2/t = m(v1 -v2)/t

In this equation, if we multiply both sides by t, we get new equation as F X t = m X (v1 -v2); F. t = m(v1 -v2)

On the right side of the equation is change in momentum of the body, and on the left side is an important property of the body known as Impulse.

Thus Impulse = change in momentum

Impulse is an important concept in the study of collisions and the above equation is an important one known as impulse-momentum change equation. When we talk about impulse, we are really talking about change in momentum of a moving body, and the rate of change in momentum is the force applied upon the body.

In brief:

Momentum vs Impulse

• Since impulse is only change in momentum, it has same units as that of momentum which is kg m/s

• Impulse is also defined as force acting for duration upon a body

• Momentum of a moving body is the product of its mass and its velocity whereas impulse is change in momentum which is the product of mass and difference in velocities.

Related Links:

1. Difference Between Impulse and Force

2. Difference Between Momentum and Energy