A particle having mass m is projected with a velocity v0 from a point P on a horizontal ground making an angle θ with horizontal. Find out the torque about the point of projection acting on the particle when it is at its maximum height?
τ = F r sin θ
As r sin θ is nothing but the horizontal component of r which is half of the Range, R.
τ=Fr sinθ=mgR2=v20sin2θ2gmg
τ=mv20sin2θ2