Answer:
Step-by-step explanation:
Wall reactions are never constant as the ladder angle decreases from vertical.
I will ASSUME that the MAXIMUM wall reaction is 40 N before slippage occurs.
Let θ be the ladder angle to horizontal
Moments about the ladder foot will sum to zero
40[5sinθ) - 100[(5/2)cosθ = 0
40[5sinθ) = 100[(5/2)cosθ
200sinθ = 250cosθ
sinθ/cosθ = 250/200
tanθ = 1.25
θ = 51.34019174...
θ = 51°