Given,
The mass of the box, m=10 kg
The force with which the box is being pushed, F=10.0 N
The net force acting on the box, Fₙ=8.0 N
The net force acting on the box is given by,
Where f is the frictional force.
On substituting the known values,
The frictional force is given by the product of the normal force (N) and the coefficient of friction(μ).
And the normal force is given by,
Thus the frictional force is given by,
Where g is the acceleration due to gravity.
On substituting the known values,
Thus the coefficient of the friction is 0.02