Impulse

Definition

Impulse is the product of the average force and the time interval over which it acts on an object. It is equal to the change in momentum of the object.

5 Must Know Facts For Your Next Test

1. Impulse can be calculated using the formula $J = F_{avg} \Delta t$, where $J$ is impulse, $F_{avg}$ is average force, and $\Delta t$ is the time interval.
2. Impulse has both magnitude and direction; it is a vector quantity.
3. The units of impulse are Newton-seconds (Ns) or kg·m/s.
4. The Impulse-Momentum Theorem states that impulse applied to an object equals the change in its momentum: $J = \Delta p$.
5. In collisions, impulse can help determine how forces act during contact and how they affect objects' velocities.

Review Questions

• How do you calculate impulse if you know the average force and time interval?
• What physical quantity does impulse equal to according to the Impulse-Momentum Theorem?
• Why is impulse considered a vector quantity?

Related terms

Momentum:

The product of an object's mass and velocity. It is a vector quantity represented as $p = m v$.

Collision:

An event where two or more bodies exert forces on each other for a relatively short period.

Force:

An interaction that changes the motion of an object. It can cause an object with mass to change its velocity.