Question

You are driving directly behind a pickup truck, going at the same speed as the truck. A crate falls from the bed of the truck to the road. (a) Will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) During the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?

Short answer

1. The car will not hit the crate before the crate hits the road if you neither brake nor swerve
2. Horizontal speed of the crate is same as that of the truck.

Step-by-step solution

To understand the concept

The problem deals with the Newton’s first law of motion. It states that if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.

(a) Will the car hit the crate before the crate hits the road if you neither brake nor swerve?

The car will not hit the crate because both vehicles are moving at a constant speed with the same frame of references. Also, when the crate falls from the truck, there will be no external force acting on it, therefore according to Newton’s first law, it will have same velocity as that of the truck. Hence, it will not be able to hit the car before it hits the ground.

(b) During the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck

As air drag acting on crate is negligible, horizontal speed of the crate is same as that of the truck