A worker pulls a 200-N packing crate at constant velocity across a rough floor by exerting a force F = 55.0 N at an angle of 35.0 degrees above the horizontal. What is the coefficient of kinetic friction of the floor?

Answer 1

Wc = m * g = 200 N.
m * 9.8 = 200
m = 20.41 kg. = Mass of crate.

F = 55N.[35o.]

55*cos35 - Fk = m*a
45.05 - Fk = m*0 = 0
Fk = 45.05 = Force of kinetic friction.

u = Fk/Wc = 45.05/200 = 0.225