Question

A man pushing a crate of mass m = 92.0 kg at a speed of v = 0.860 m/s encounters a rough horizontal surface of length = 0.65 m as in the figure below. If the coefficient of kinetic friction between the crate and rough surface is 0.355 and he exerts a constant horizontal force of 300 N on the crate, find the following.

Find the magnitude and direction of the net force on the crate while it is on the rough surface.

Answer 1

The net force in the "rough patch" is the pushing force minus the kinetic friction force.

Fnet = 300 - M*g*0.355 = -20 N

The crate will decelerate at a rate
a = Fnet/M = 3.38 m/s^2
It will continue moving for a time
t = Vo/a = 0.254 seconds, at which time it will stop after traveling 0.11 meters
The applied force will not be enough to move it farther.

Answer 2

i dont know