Conservation of Momentum in an Inelastic Collision
The momentum and energy of to colliding blocks is displayed. The elasticity of the collision can be varied along with the mass and speed of the blocks. Even if the collision is not elastic and energy is lost during the collision, the momentum can be seen to be conserved.

Two Dimensional Collisions
A moving puck makes an off center collision with a stationary puck on a frictionless surface. Displayed are the components of momentum in the x and y directions. The separation between the centers of the two pucks can be adjusted to observe the resulting outcome of the collision. The masses and initial speed of the first puck can also be varied.

Frame of Reference in a Collision
Three different shaped objects collide with each other. One can view the collision from either the normal lab frame, a frame moving with each of the objects, or the center of mass frame.

Frames of Reference for a Moving Spring
Two blocks are connected by an initially unstretched spring and one block is given an initial velocity. The subsequent motion can be viewed in either normal lab frame, a frame moving with each of the objects, or the center of mass frame. Gravity can also be turned on or off to observe the motion of the blocks.

Atomic Motion During a Collision (248K)
No Tape Version (34K)
Simulated is an 8x8 two-dimensional array of atoms joined by lattice work of springs representing inter atomic forces. The "simulated-solid" is dropped onto a rigid surface. One can observe that the translational kinetic energy of the "simulated-solid" transforming into random vibrational energy of the individual atoms during the collision.
QT Sovie Solid collides aliened with the Surface (420K)
QT Movie Solid collides tilted relative to the Surface (520K)

If the spring constants ("interatomic forces") are made small then the simulation represents what happens in high energy collision in which there is enough macroscopic kinetic energy to melt the solid. Atomic Collision Meltdown QT Movie (236K)

Collisions and Center of Mass
A moving object collides with a stationary object. The collision is only partially elastic. Displace is the motion of the center of mass as well as the values of the momentum, velocity, and energy of the objects in both the lab rest frame and the center of mass frame. The action can be viewed in both the lab and center of mass frame. Collision and Center of Mass

Changing Directions on Thin Ice
A person and his fishing cabin are sliding towards thin ice. The person pushes the cabin hard enough that he reverses his direction. Both their initial speed and the duration of the push can be varied along with their masses. Displayed are their velocities, momentum, and energy both before and after the push. Changing Directions Problem

Mobile Cannon
A cannon is mounted on a mobile platform. The cannon fires a shell with a given muzzle velocity. Displayed is the platform recoil velocity when the breaks are off. The muzzle velocity and mass of the shell can be varied along with the mass and initial velocity of the platform. Mobile Cannon Problem