Question

`find normal force acting on block & value of force F for equilibrium of block `

Answer 1

From the question we know that the block is in equilibrium 

so when we resolve the angle the force F makes with the horizontal we get Fcos60 is the force that keeps the block in equilibrium against the 100N force ,so

100N=Fcos60

100N=F/2

Therefore F=200N

The normal force or normal reaction is again got got by resolving F

N_r=Fsin60(where N_r is the normal reaction)

N_r=200(√3)/2

N_r=100(√3)N