A flywheel is a rotating mechanical device that is used to store rotational energy. The amount of energy stored in a flywheel is proportional to the square of its rotational speed. Due to this relationship, Flywheels make excellent instruments for experimentation on Moment of Inertia. Consists of cast iron, wheel about 20cm diameter and 4.4cm wide edge carefully machined & balanced on a horizontal shaft held in ball-bearings on strong Iron brackets. The wheel is marked with a line and a pointer is fixed to the bracket which together help in accurately counting the number of revolutions the wheel completes. Diametric hole is drilled on the shaft to accommodate a pin and chord. The base is provided with four holes so that apparatus can be fixed on a wall. Complete with cord and hook