UNIT 05  Systems of Particles  Momentum

1. CENTER OF MASS (study guide is HERE) 
A) Students should understand the technique for finding center of mass, so they can: (C.O.M study guide) 
(1) Identify by inspection the center of mass of a symmetrical object (4.1) 
(2) Locate the center of mass of a system consisting of two such objects (C 4.2) 
(3) Use integration to find the center of mass of a thin rod of nonuniform density (C 4.3) 
B) Students should be able to understand and apply the relation between centerofmass velocity and linear momentum, and between centerofmass acceleration and net external force for a system of particles (C 4.4) 
C) Students should be able to define center of gravity and to use this concept to express the gravitational potential energy of a rigid object in terms of the position of its center of mass (C 4.5) 
2. Impulse and momentum
Students should understand impulse and linear momentum, so they can: 
A) Relate mass, velocity, and linear momentum for a moving object, and calculate the total linear momentum of a system of objects (C 4.6) 
B) Relate impulse to the change in linear momentum and the average force acting on an object (C 4.7) 
C) State and apply the relations between linear momentum and centerofmass motion for a system of particles (C 4.8) 
D) Calculate the area under a force versus time graph and relate it to the change in momentum of an object (C 4.9) 
E) Calculate the change in momentum of an object given a function for the net force acting on the object (C 4.10) 
3. Conservation of Linear Momentum, Collisions 
A) Students should understand linear momentum conservation, so they can: 
(1) Explain how linear momentum conservation follows as a consequence of Newton’s Third Law for an isolated system (C 4.10) 
(2) Identify situations in which linear momentum, or a component of the linear momentum vector, is conserved (C 4.11) 
(3) Apply linear momentum conservation to onedimensional elastic and inelastic collisions and twodimensional completely inelastic collisions (C 4.12) 
(4) Apply linear momentum conservation to twodimensional elastic and inelastic collisions (C 4.13) 
(5) Analyze situations in which two or more objects are pushed apart by a spring or other agency, and calculate how much energy is released in such a process (C 4.14) 
B) Students should understand frames of reference, so they can: 
(1) Analyze the uniform motion of an object relative to a moving medium such as a flowing stream (C 4.15) 
(2) Analyze the motion of particles relative to a frame of reference that is accelerating horizontally or vertically at a uniform rate (C 4.16) 