tag:techtv.mit.edu,:Array/185073180 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 tag:techtv.mit.edu,:Array/185052360 2009-06-11 14:02:02 -0400 MIT Department of Physics Technical Services Group An air puck is attached to a string that passes through the center of an air table. A weight is attached to the end of the string. The ball is set into rotation in a horizontal circle. When the weight is released, creating a constant force inwards, the radius of the path is shortened and the puck speeds up. A similar effect is seen when the string wraps around a center rod like a tether ball. This creates an increasing force, which causes the puck to inspiral more quickly. 181