What impulse must act on the bowling ball to stop it?

[x2017]

Homework Statement

[/B]
A 10kg bowling ball is moving with a velocity of -3m/s.
a) What is the momentum of the bowling ball?
b) What impulse must act on the bowling ball to bring it to a stop?

Homework Equations

momentum=mv
impulse=ΣFΔt
ΣFΔt=mΔv

The Attempt at a Solution

a) momentum = mv
momentum = (10)(-3)
momentum = -30Ns

b) This is where I get stuck. Is the impulse simply equal and opposite to the momentum? Or is there another step?

ΣFΔt=mΔv
ΣFΔt=-30Ns
ΣFΔt=30Ns (opposite sign because bowling ball has to be stopped by a force going in the other direction)

 

[gneill]

Impulse represents a change in momentum. The change you want in this case happens to be equal in magnitude to the initial momentum of the bowling ball. So you've done fine.