1 pts
An elephant of mass 6000 kg stands near the back of an open
railroad car of mass 80,000 kg. Both are initially stationary on a
level track, with the car free to move on the track. An observer
marks the initial position of the elephant on the ground below the
car. The elephant then walks to the front of the car. The observer
marks the final position of the elephant on the ground, and
measures the distance between the two marks to be 15 m. How
far does the car move during this time, and in which direction?
2.2 m, backward