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

1200kg car moving at 9.72m/s runs into and sticks to a parked 1000kg car. The collision takes 0.15s and after the crash the cars wheels lock and they skid to a stop on u=0.40 road. What is the impact force on both cars?

**2. Relevant equations**

J=F*t=m*dv

**3. The attempt at a solution**

I’ve found the distance it takes for it to stop (3.68m) and also the speed after the crash (5.3m/s).

I used the momentum to divide by the time (0.15s) to get the impact force, but the answer is wrong.

http://ift.tt/1cTABMd