p before =p after

 Within a closed system (a system that does not exchange energy with the outside environment) momentum is always conserved.  Momentum can neither be gained or lost within a closed system.

 If a bicyclist traveling at maximum speed runs into a stationary dump truck, what happens?  If a dump truck moving at 5 m/s runs into a stationary bicyclist, what happens?  If a dump truck moving at 30 m/s runs head-on into a bicyclist at maximum speed, what happens?

 If two objects with equal mass, traveling at the same speed, get into a head-on collision, what happens?

 A child and her father are standing still in the center of an ice rink. If the child tries to push her father, what will happen?  Desk chair demo

 In the collision of any two objects, the added momentum of both objects has to be the same before and after the collision  p before =p after

 Elastic ◦ Two objects collide and bounce off of each other with no deformation  Inelastic ◦ Two objects collide with each other, crumple and deform, and sometimes stick together  Explosion ◦ When one object becomes two or more objects ◦ In a conventional explosion, one object breaks into many pieces that fly in all directions