Question

To find the magnitude of the normal force, you must express Fn in terms of Fw since Ff is an unknown. Using the equations you found in the two previous parts, find an expression for Fn involving Fw and θ but not Ff.CosθFf - sinθFn = 0FfSinθ + FnCosθ - Fw = 0

Answer 1

cosθFf-sinθFn=0 (1)

cosθFn+sinθFf-Fw=0 (2)

multiplying (1 ) by sinθ and (2) by cosθ

and substracte (2) - (1)

hence we get

∴ Fn=Fwcosθ