Answer:
20 N
Explanation:
There are two forces acting on the box:
- The force of push, F, forward, of magnitude F = 20 N
- The force of friction, [tex]F_f[/tex], backward
So, the equation of motion for the box is
[tex]F-F_f = ma[/tex]
where
m = 5.0 kg is the mass of the box
a is its acceleration
The box is sliding at constant velocity: this means that its acceleration is zero
a = 0
So, the equation becomes
[tex]F-F_f = 0[/tex]
Therefore, we can find the magnitude of the force of friction:
[tex]F_f = F = 20 N[/tex]