p6 8

• Change in momentum


  The difference between the final and initial momentum
• Conservation of momentum principle


  When the net external force is zero, the total momentum of the system is conserved or constant
• Elastic collision


  A collision that also conserves internal kinetic energy
• Impulse


  The average net external force times the time it acts; equal to the change in momentum
• Inelastic collision


  A collision in which internal kinetic energy is not conserved
• Internal kinetic energy


  The sum of the kinetic energies of the objects in a system
• Isolated system


  A system in which the net external force is zero
• Linear momentum


  The product of mass and velocity
• Perfectly inelastic collision


  A collision in which the colliding objects stick together
• Point masses


  Structureless particles with no rotation or spin
• Quark


  Fundamental constituent of matter and an elementary particle
• Second law of motion


  Physical law that states that the net external force equals the change in momentum of a system divided by the time over which it changes