C4-21
Illustrate the second law of motion. Experimentally determine the acceleration due to gravity.

This classic demonstration illustrates motion under the acceleration of gravity. When used carefully, approximate measurements can be made.

Equal masses M of 200 grams are hung on the ends of a light string passing over a light, frictionless pulley. When an additional mass of 100g is hung on one end, the resulting acceleration can be measured by timing the motion of either mass over a distance S between two points. The acceleration of gravity g can then be calculated: g = a (2M + m)/m, where a is the acceleration of the system: a = 2S /t^2.
C4, FS2, ME1