Calculating Impulse in a Collision: Simple Physics 11 Homework Problem

[roxxyroxx]

Homework Statement

A 15.0 g object initially moving to the right at 30.0 cm/s collides with a stationary 45.0 g object. After the collision the 45.0 g object is moving to the right at 15 cm/s.
what impulse does the 45.0 g object apply to the 15.0g object during collision?

Homework Equations

F\Deltat = m\Deltav

The Attempt at a Solution

I tried:
F\Deltat = m\Deltav
= (15.0g)(15.0cm/s)
= 225 N x s
but the answer is 6.75 x 10^-3 N x s
help ?

 

[Doc Al]

I tried:
F\Deltat = m\Deltav
= (15.0g)(15.0cm/s)
= 225 N x s
but the answer is 6.75 x 10^-3 N x s

How did you determine the change in velocity of the 15.0g object?

(Also: Use standard units. Convert g to kg; cm to m.)