Homework Help: Momentum problem: object struck with stick

1. The problem statement, all variables and given/known data

A stationary 1.67 kg object is struck by a stick. The object experiencees a horizontal force given by F = at - bt^3, where t is the time in milliseconds from the instant the stick first contacts the object. if a = 1500 N/ms and b = 20 N / ms^3, what is the speed of the object just after it comes away from the stick (t = 2.74 ms)?


2. Relevant equations



3. The attempt at a solution

I integrated to come up with the impulse J_x. Then I added it to p_0 = 0. The integral solved at the limits of 0 to 0.00274 = 0.005631. I divided this by the mass 1.67 to get the velocity. This gave v = 0.003372 which is not right...

What did I do wrong?

Thanks

 

I'm integrating to get an impulse, then using it to get velocity from the momentum equation. The problem is about momentum.

 

I integrated with limits of 0 to 0.00274, so it's in seconds. So that result should be J_x, and dividing out mass should give velocity. I don't see where I could have messed up units, offhand.

 

Thank you.