f = Fw, N = W, and Fw sin = 1/2 W cos f: force of friction between the ladder and the ground, Fw: normal force on the ladder due to the wall, : angle...

f = Fw, N = W, and ℓ Fw sin θ = 1/2 ℓ W cos θ

f: force of friction between the ladder and the ground, Fw: normal force on the ladder due to the wall, θ: angle between the ladder and the ground, N: normal force on the ladder due to the ground, W: weight of the ladder, and ℓ: length of the ladder.

Determine the smallest angle θ for which the ladder remains stationary. Answer in units of ◦ .