tag:techtv.mit.edu,:Array/186611580 2008-10-10 14:24:44 -0400 MIT Department of Physics Technical Services Group Two carts are connected together on an air track with a spring. Under bright lights you can see the coupled oscillation of the carts back and forth, but under black lights you can see that the center of mass moves at a constant velocity. 103 tag:techtv.mit.edu,:Array/186491840 2009-06-10 14:04:53 -0400 MIT Department of Physics Technical Services Group Two pucks of the same mass are slid at each other on an air table, and their resulting collisions demonstrate conservation of momentum. Notice on the first collision, for example, that when a moving puck hits a stationary puck dead-on, that the second puck leaves with the same velocity as the first, and the first puck stops moving completely. 80