Answer:
F = mg /μ
Explanation:
For this exercise we define a coordinate system with the horizontal x axis and the vertical y axis, let's write the equilibrium equations for each axis
X axis
F -N = 0
F = N
Y axisy
fr - W = 0
fr = W (2)
the force and touch have the expression
fr = μ N
we substitute
fr = μ F
we substitute in 2
μ F = m g
F = mg /μ