Last modified on 20 July 2009, at 20:54

School Science/Rotational Inertia Experiment

Set up a turntable with a pulley attached to a bench top nearby. Wind a string around the central axel of the turntable at a fixed radius, and hang over the pulley with a stack of masses attached to this end. Release the mass stack and time how long it takes to fall to ground, thus rotating the turntable with a particular torque for a fixed angular displacement.(ex/ 5 revolutions) Adjust the applied torque by changing the mass stack value, and time again for the same angular displacement. Repeat for three or more further values of the mass stack, each time recording the time it takes for the turntable to complete the fixed angular displacement chosen (ex/ 5 revolutions) Using the gathered data it is possible to calculate the angular acceleration of the turntable for each value of torque applied, then plot a graph of these to calculate the gradient, which equals the rotational inertia I of the turntable. Further experiments could involve adding mass to the turntable at various radial distributions to demonstrate the effect of increasing the rotational inertia.