An experiment with components of force

 

I recently rediscovered this practical from the old Nuffield course. The angled force T can be said to be made up of a horizontal component H and a vertical component V. A little trigonometry will show that for horizontal equilibrium, Tsin(theta) = F and for vertical equilibrium Tcos(theta) = W. We worked on the latter and plotted cos(theta) on the y-axis against 1/T on the x-axis. It's not easy to get clean data to get a straight line but the gradient = W and can be checked against the true value.