Unit 1/2 momentum question

[andysalter]

In a game of snooker a player hit's a 0.2 kg ball with the cue, exerting a force of 40N on the ball for 12 milliseconds.

a) What impulse is exerted on the ball?

I = f x t = 40 (in newtons) x 0.12 (in seconds) = 4.8 Ns    the answer says 0.48 Ns, what did I do wrong?

b) What is the change in momentum of the ball?

Newton's 1st law? Final momentum = initial momentum
therefore momentum = 4.8 kg ms^-1     answer says 0.48 kg ms^-1

c) With what velocity will the ball leave the cue?

I = m x V  =>  V = I / m  =   4.8 / 0.2 = 24 ms^-1    answer says 2.4 ms^-1


all the answers are the same as mine just divided by 10... where did I need to do that?

[Professor Polonsky]

12 ms = 0.012 s

That's all.

[andysalter]

hahahaha I feel stupid now, thanks 

[Guest]

Time conversions - notorious for tripping Physics students over