Question

During a spate of stop-and-go traffic on the highway, you are twiddling your thumbs, waiting for the traffic to start moving when a truck rear-ends you, boosting your car's speed to 5 mi/hr. The truck's speed is 1.75 mi/hr after the collision. What was the truck's speed before it collided with you? Assume that the truck is about 4 times more massive than your car. Also, assume that you can neglect effects like friction.

Answer 1