Calculating Work Done for a Box on Horizontal Floor

[chawki]

Homework Statement

A box, whose weight is 182 kg, is drawn with constant speed 21 m along a horizontal concrete floor. The kinetic friction between the box and the floor is 0.58.
(acceleration due to gravity, g = 9,81 m/s2).

Homework Equations

Calculate the work done when the box is drawn with a horizontal force.

The Attempt at a Solution

W = F*d
i don't know how to find F
i could only find F_f which is the frictional force
F_f= 0.58*182*9.81
F_f= 1035.54 N

 

[tiny-tim]

hi chawki!

W = F*d
i don't know how to find F
i could only find F_f which is the frictional force
F_f= 0.58*182*9.81
F_f= 1035.54 N

the speed is constant, so the acceleration is zero,

so F_total = 0,

so F + F_r = 0

 

[supratim1]

applied force is equal to force of friction in magnitude. so job is done!

 

[chawki]

yesyes,
by applying Newton second law and by projection on xx, we get:
F-F_f=0
F=F_f
F=0.58*182*9.81
F=1035.5436 N

W=F*d
W=1035.5436*21
W=21746.4156 J