A friend comes up to you and because he is a giant nerd, he offers the following physics riddle. A train is moving along the track at 45 m/s (approximately 100 mph) at a constant velocity. (Ignore wind resistance and friction). Ahead on the track is a semi-truck that has stalled on the road just as it was crossing the tracks. According to Newton's second law of motion, F=MA. When the train gets to the truck, it will crash into the truck and cause a lot of damage but why since according to Newton's 2nd Law, there is no force present...the train is moving at constant velocity so Acceleration is ZERO. In this case then, Force = Mass * 0. But damage is still done even though there is not force present? How would you answer your friend's riddle?