What is the minimum value of F needed so that block begins to move upward on frictionless incline plane as shown:-

a )Mg tan (θ/2)
b) Mg cot (θ/2)
c) Mg sin θ/(1 + sin θ)
d) Mg sin (θ/2)

Question

What is the minimum value of F needed so that block begins to move
upward on frictionless incline plane as shown:-

a )Mg tan (θ/2)
b) Mg cot (θ/2)
c) Mg sin θ/(1 + sin θ)
d) Mg sin (θ/2)

Vara · Accepted Answer

Under equilibrium conditions:Mgsinθ=F+FcosθMgsinθ=F1+cosθF=Mgsinθ1+cosθ   =Mg2sinθ2cosθ22cos2θ2   =Mgtanθ2Ans:Option-1