if you use a horizontal force of 30 N to slide a 12 kg wooden crate across a floor at a constant velocity, what is the coefficient of kinetic friction between the crate and the floor?

Answer 1

Wb = M*g = 12 * 9.8 = 117.6 N. = Normal
force, Fn.

Fx-Fk = M*a.
Fx-Fk = M*0 = 0.
Fk = Fx = 30 N.

Fk = u*Fn.
u = Fk/Fn = 30/117.6 = 0.255.

Note: Since the velocity is constant, the acceleration is zero.

Answer 2

A 200kg crate is pushed horizontally with a force of Fa= 700N if the coefficient of friction is right to left muk=0.2 calculate the acceleration of the crate?