Chapter 7 Systems of particles 7-1 The motion of a complex object 7-2 TWo-particle system 7-3 Many-particle system 7-4 Center of mass of solid objects 7-5 Conservation of momentum in a system of particles
Chapter 7 Systems of particles 7-5 Conservation of momentum in a system of particles 7-4 Center of mass of solid objects 7-3 Many-particle system 7-2 Two-particle system 7-1 The motion of a complex object
When can the object studied be regarded as a mass point? Doing only translational motion Translational motion Rotational motion Translational Rotational motion Ih Em
When can the object studied be regarded as a mass point? Doing only translational motion Translational + Rotational motion Translational motion Rotational motion
7-1 The motion of a complex object When we projectile a rigid body, the motion of the body looks very complicated We can consider the motion of the rigid body to be a combination of a parabolic trajectory of a"center of mass"(rotational motion is not considered) plus a rotation about center of mass"(translational motion is not considered) How to find the center of mass (CM) of a particle system?
7-1 The motion of a complex object When we projectile a rigid body, the motion of the body looks very complicated. We can consider the motion of the rigid body to be a combination of a parabolic trajectory of a “center of mass” (rotational motion is not considered) plus a rotation about “center of mass” (translational motion is not considered). How to find the center of mass (CM) of a particle system?
7-2 TWO-particle system Do an experiment to find cm in a two-particle system As an example we consider a baton consists of two particles m, m, at its ends a and B connected by a thin rigid rod of fixed length and negligible mass B
7-2 Two-particle system As an example, we consider a baton consists of two particles , at its ends A and B, connected by a thin rigid rod of fixed length and negligible mass. m2 = 2m1 m1 m2 m1 m2 A B Do an experiment to find CM in a two-particle system
We give the rod a push along the frictionless horizontal surface and examine its motion Snapshots of the locations of points a and B at successive intervals of time Clearly both m, and m2 are accelerated, however, one point in the rod(point c moves with constant velocity
Clearly both and are accelerated, however, one point in the rod (point C) moves with constant velocity. m1 m2 We give the rod a push along the frictionless horizontal surface and examine its motion. Snapshots of the locations of points A and B at successive intervals of time