Chapter 4, Problem 45P

(a)

To determine

The kinetic frictional force that acts on the box when the elevator is stationary.

(b)

To determine

The kinetic frictional force that acts on the box when the elevator is accelerating upward with an acceleration magnitude $1.20\frac{\text{m}}{{\text{s}}^{\text{2}}}$.

(c)

To determine

The kinetic frictional force that acts on the box when the elevator is accelerating downward with an acceleration magnitude $1.20\frac{\text{m}}{{\text{s}}^{\text{2}}}$.