Impulse

Impulse is the change in momentum over time Momentum changes due to a force, so you can also think of impulse as force x time

Impulse = change in momentum Momentum = mass· velocity P = m· v Imp = mvf – mvi Units = Ns

Imp = mvf – mvi Imp = .5(40) - .5(0) = 20 Ns In a penalty kick a soccer player increases the speed of the ball from 0 to 40 m/s. The mass of the soccer ball is .5 kg. What impulse does the soccer player give the ball? Imp = mvf – mvi Imp = .5(40) - .5(0) = 20 Ns

Impulse = Force x time Imp = F x t Units = Ns

If the soccer player is in contact with the ball for If the soccer player is in contact with the ball for .1 second, what is the force exerted on the ball? Imp = F x t 20 = F (.1) 200 N = F