2.The relation between torque and angular momentum Differentiating Eq(10-1) we obtain l dr x P+rx ∑F=x(106) Here ar dr the×P=yXP=0 d p and dt ∑ Eq(10-6) states that "the net torque acting on a particle is equal to the time rate of change of its angular momentum2. The relation between torque and angular momentum Differentiating Eq(10-1) we obtain (10-6) Here , the → → → → → → → → =  +  = rF =  dt d P P r dt d r dt d L → → = v dt d r  =  = 0 → → → → P v P dt d r and Eq(10-6) states that “the net torque acting on a particle is equal to the time rate of change of its angular momentum.  → → = F dt d P