a 2000-kilogram car uses a breaking force of 12000 newton's to stop in 5 seconds. what impulse acts on the car?

i honestly don't even know but yahoo answers says:

Impulse causes momentum to change, which means:

Impulse = change in momentum, or in equation form:

F∆t = (mv) 2 - (mv) 1

so p (impulse) = mass times velocity so the mass is 2,000kg and the velocity is 12,000N/5s.

speed is basically velocity so you have to calculate how many newtons per one second, so 12,000/5s- - just divide the numerator and denominator by 5. Also, velocity and speed are measured in N/s.