Center of Mass
Motion with Many Particles Real objects consist of many particles. The particles are bound by internal forces. The object moves as if it were a single particleThe object moves as if it were a single particle Parts of the object may appear to move independently.
Forces on One Particle There is a net force on each particle in an object. This corresponds to the particle’s acceleration. mimi riri
Force on a System For N particles in a system the forces add. Some forces are internal and some are external to the system. m2m2 m3m3 m4m4 m1m1
Internal Forces Within an object all the forces are in pairs. These forces must cancel out in the sum.
Total Mass The sum of all the individual masses in a system is the total mass.
Center of Mass The weighted average of the positions of the particles is the center of mass. m2m2 m3m3 m4m4 m1m1 r CM
Translational Motion The motion of the center of mass of a system of particles depends on the net external force on the system. next M F net r CM