Posted 23 April 2006 - 10:09 PM
A mass suspended on a spring when pulled and released will oscillate in simple harmonic motion. If we consider the forces acting on a mass hung on a spring we have:
weight of the mass = restoring force of the spring (so the system is in equilibrium)
thus mg = kx
then k/m = g/x
Then in simple harmonic motion T = 2pi x sq.rt. (m/k)
substituting m/k for x/g into the Time period equation. you now have an equation with x and g in it. Square both sides to get
T^2 = (4pi^2)x/g then set several extension for the spring x and let the system oscillate, measure the Time period T for each oscillation, find T^2 and plot against x the extension. From the graph the gradient equals 4pi^2 /g then solve for g.