810.3 The angular momentum of a system of particles and moment of inertia of rigid body -the perpendicular distance of each mass dm from the axis of rotation The element of mass: adl linear density: a dm= ds surface density: o pdv volum density P 8 10.3 The angular momentum of a system of particles and moment of inertia of rigid body Examplel: 5 particles are connected by 4 light staffs as shown in figure. Find the moment of the system with respect to the axis through point A, and perpendicular to the paper plane. Solution:I=∑m ●4 I=2m12+3m(2) n +(4m+5m)(√2l) =32ml 5m 1010 --the perpendicular distance of each mass dm from the axis of rotation r⊥ dm = λdl linear density：λ σdS surface density：σ ρdV volum density：ρ The element of mass: §10.3 The angular momentum of a system of particles and moment of inertia of rigid body l l l l A m 2m 3m 4m 5m 2 2 2 2 32 (4 5 )( 2 ) 2 3 (2 ) ml m m l I ml m l = + + = + Example1: 5 particles are connected by 4 light staffs as shown in figure. Find the moment of the system with respect to the axis through point A, and perpendicular to the paper plane. Solution: 2 = ∑ i⊥ i i I m r §10.3 The angular momentum of a system of particles and moment of inertia of rigid body