Impulse

F = Δp/t Δp = Ft Impulse is defined as the force times the

time over which the force acts Impulse = Ft = Δp In order to change the momentum of an

object, two quantities are important (Force and time)

Equation

Golf – to impart the greatest momentum to a ball, its not only the force you hit the ball with but also how long you’re in contact that matters

Why use a seat belt?

For Example

Area under a force vs. time curve is impulse which is equal to the change in momentum

Graphically

Assuming a 65g tennis ball started from rest and the force of impact of the racket on the ball is represented below, what is the impulse acting on the ball and its final speed?

Example

A billiard ball of mass 200g rolls towards the right-hand cushion of a billiard ball table at 2.0 m/s and rebounds straight back at 2.0m/s. A) What impulse acts on the ball? B) If the time of interaction is 2.0s, what force acts on this ball?

Example

A 2.0 kg skateboard is rolling across a smooth floor when a girl kicks it causing it to speed up to 4.5m/s in .50s. If she exerts a force of 6.0N while kicking, what was it’s initial velocity?

Example

A) Calculate the impulse experienced when a 70kg person lands on firm ground after jumping from a height of 3.0m. B) If it takes .003 s to stop when landing straight legged, what is the force of impact? C) If it takes .13s to land when your knees are bent, what is the force of impact?

Example