You are a traffic accident investigator. you have arrived at the scene of an accident. two trucks of equal mass (3,000 kg each) were involved in a rear-end accident at a stop sign. here is what you know:

- truck 1 started from rest at the top of a 22-meter hill and coasted toward the intersection.
- truck 2 was on a flat stretch of road at the bottom of the hill directly in front of truck 1.
- at the bottom of the hill, truck 1 was going 20 m/s; truck 2 was going 35 m/s.
-there were no skid marks left by truck 2. the collision occurred at the stop sign where truck 2 had stopped.
- after the collision, both trucks moved together in the same direction at 10 m/s before slowly rolling to a stop.

1. what was the kinetic energy of each truck before they began braking?

2(a). how much energy did truck 1 lose from the top to the bottom of the hill?

(b) where do you suppose that energy went?