LINEAR MOMENTUM

2. IMPULSE

1.2 Impulse

Impulse is usually associated with collision. When a body collides with another, each receives an impulse or blow. The impulse consists of a large varying force acting for a very short time.

Impulse is defined as the product of the average force acting on a particle and the time during which it acts.

If a force F acts for a short time t, impulse I is given by

            I = F x t

The unit of impulse is Newton-second (Ns). Impulse is a vector. It has the same direction as the direction of the force.

a.       A racket hitting a ball

b.      A football player colliding with another player.

c.       A car moving at a constant velocity

d.      An object moving in a projectile motion

1.2.1 Examples

1. A stationary ball is hit by an average force of 50N for a time of 0. 03s.What is the impulse experienced by the ball?

2. A ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2ms^-1 and rebounds with the same speed. Determine the impulse experienced by the ball.