Answer:
c) 500 N
Explanation:
If the block moves with constant speed there is no acceleration. We draw a free body diagram and define the forces on the body.
[tex]F_{f}=FrictionForce\\F_{e}=ExternalForce\\N=NormalForce\\W=Weight\\[/tex]
The equation for the frictional force is:
[tex]F_{f}=N*H_{k}[/tex]
Where [tex]H_{k}[/tex] is the kinetic friction coefficient. We write the equilibrium equation in the y direcction:
[tex]\sum F_{y}\rightarrow N-W=0\\N=W[/tex]
We replace this result in the equation for the frictional force:
[tex]F_{f}=W*H_{k}[/tex]
We replace the data given by the exercise and find the weight
[tex]W=\frac{F_{f}}{H_{k}}\\W=\frac{100}{0.2}=500\: N[/tex]
