Answer:
We need to (at least) apply a force of 9.8 N to move the block
Explanation:
Second Newton's Law
If a net force [tex]F_n[/tex] different from zero is applied to an object of mass m, then it will move at an acceleration a, given by
[tex]F_n=ma[/tex]
If we apply a force F to an object placed on a rough surface, the only way to make it move is to beat the friction force which is given by
[tex]F_r=\mu F_N[/tex]
Where [tex]\mu[/tex] is the static friction coefficient and [tex]F_N[/tex] is the normal force exerted by the table to the object. Since there is no motion in the vertical direction the normal force equals the weight of the object:
[tex]F_N=mg=5\ kg\ 9.8\ m/s^2=49\ N[/tex]
The friction force is
[tex]F_r=0.2 (49)=9.8\ N[/tex]
Thus, we need to (at least) apply a force of 9.8 N to move the block
