A 1.36 103-kg car traveling initially with a speed of 20.0 m/s in an easterly direction crashes into the rear end of a 9.00 103-kg truck moving in the same direction at 15.0 m/s. The velocity of the car right after the collision is 13.0 m/s to the east. What is the velocity of the truck right after the collision? (Assume east is the positive direction. Indicate the direction with the sign of your answer.)
m/s
How much mechanical energy is lost in the collision? (Use the exact value you entered the first part to make this calculation.)
J