Question

What is the impulse on a 5-kg ball rolling at 2 m/s when it bumps into a pillow and stops?
Answer

Answer 1

Impulse = change of momentum.

How much does the momentum of the ball change?

Answer 2

-10N

Answer 3

The units of momentum are kg.m/s; which is not Newtons

Answer 4

OK -10Ns but my problem is to know if i have to live the negative sign there are they not just asking the magnitude

Answer 5

I'd say negative, because change in momentum is -10 N.s

Answer 6

Change = End - Start
= 0 - 10
= -10

Answer 7

yep its true but my real worry was to know if i have to live the negative sign there

Answer 8

Again, I say yes. That the impulse applied to the ball.

Answer 9

ok thanks