Originally Posted By: paul
but if its stopped on the earth then in reference to the earth its momentum is zero.
and it lost 1000.

Yes, same answer I got, funninly enough.

Here's where I'm going. Now the driver manages to restart his car and reverse away from the tree, he speeds up to a mometum of 1000 in the opposite direction and keeps going like that.

Q1: What was his momentum before the collision
Q2: What is his momentum after driving away
Q3: What is the overall change in momentum of the car between the start and end of the story?
Q4: How much momentum did the car lose between the start and end?

Edited by kallog (06/21/10 05:09 AM)