Two forces act an angle of 120°. If the greater force is 50 kg and their resultant is perpendicular to the smaller force, the smaller force is

ANS:B - 25 kg

Resultant force makes an angle α with the force P(in this case smaller force).

tanα = Qsinθ/(P+Qcosθ) α = 90, θ = 120, Q = 50, P =?

tanα = sinα/cosα = 1/0.

1/0 = Qsin(120)/(P+Qcos(120)) means P+Qcos(120) = 0.

Therefore P = -Qcos(120) = -50cos(120) = -50*(-1/2) = 25kg.