A particle of mass m is projected with velocity v at an angle q with the horizontal. Find its angular momentum about the point of projection when it is atthe highest point of its trajectory.

At the highest point of its trajectory velocity of projectile is v θcos in the horizontal direction and value of maximum height is hmax=v2sin2θ2g∴Angular momentum about the point of projection isL=phmax=(mvcosθ)v2sin2θ2g ⇒L=mv2cos⁡θ⋅sin2⁡θ2g⇒L=mv3sin⁡θ⋅sin⁡2θ4g