A particle of mass m is projected from point O with a horizontal velocity 'u' at time t = 0. What is its angular momentum relative to point O as a function of time?

Question

G1 Physics · Accepted Answer

r=(ut)î-½gt²ĵ and p=m(u î-gt ĵ). Thus z-component of L=xpᵧ-ypₓ=-½mgut², along -k̂. Hence A. Use angular momentum L⃗=r⃗×p⃗ (or L=Iω for a rigid body). During a short impact, angular momentum about a point with zero impulsive torque is conserved; use linear momentum/energy additionally where applicable..