Dear Student,
Please find below the solution to your problem.
As shown in the figure the Normal reaction N on the block and Vertical component of the force F are opposite to weight.
We need only horizontal motion no vertical motion so vertical force should be balanced that is net force in vertical direction should be zero, i.e., N+FCosθ−Mg=0 or N=Mg−FCosθ , put F=Mg as given in the question. so by putting so we get N=Mg(1−cosθ) .
Now putting another condition to make F able to pull the block horizontally the Fsinθ should be greater than or eual to Staticfriction and we know that maximum value of static friction is μN
so we have Fsinθ≥μN
putting value of N we get Sinθ=μ(1−cosθ)
put cosθ=1−2Sin^2(θ/2) and sinθ=2sin2θCos2θ
Thanks and Regards