A 24.0-kg block is initially at rest on a horizontal surface. A horizontal force of 78.0 N to be motionless

A 24.0-kg block is initially at rest on a horizontal surface. A horizontal force of 78.0 N is required to set the block in motion, after which a horizontal force of 63.0 N is required to keep the block moving with constant speed.

(a) Find the coefficient of static friction between the block and the surface.


(b) Find the coefficient of kinetic friction between the block and the surface.


Please help, I've been stuck on these problems since last night and they are due in 2 hours. :(

Fr = μN
Fr=resistive force of friction
μ = coefficient of friction
N = normal force

N=W=mg
N=24 * ( 9.81)= 235.44 N

78.0 N is for static friction
78 = μ (235.44 )
μ=0.33

63.0 N kinetic friction
63= μ (235.44)
μ=0.27