Question

# A box (400 kg) sits inside the trailer of a semitruck traveling at a speed of...

A box (400 kg) sits inside the trailer of a semitruck traveling at a speed of 20 m/s (~ 44 mph). Suddenly, a car in front of the truck stops in the road. The driver of the truck hits the brakes to bring the truck to a stop. Assume that the coefficient of static friction µs = 0.7 between the box and the floor of the trailer. Assume g = 10 m/s2.

When the truck slows down while traveling left, what is the direction of the friction force on box 1 (right, left, none)?

When the truck is slowing down, what is the maximum magnitude of the static friction force on box 1 (to slow it down with the truck and not let it slide)?

When the truck is slowing down, what is the maximum magnitude of the truck's acceleration such that box 1 does not slide?

What is the minimum time for the truck to stop such that box 1 does not slide? Use your maximum acceleration from the previous problem.

Given this minimum time, what is the minimum distance for the truck to stop without box 1 sliding?

Let me know if you need any further clarification on this.