metal barrel t. So the period: T=-I. The previously measured To can be used b) The theoretical equation for the moment of inertia of a barrel is 1,=m(Di+D2). Calculate the experimentally measured value I and the theoretical value I,. Calculate the percentage difference between ther Data table no. 3: 2 Inner diameter D/cm Outer diameter D2/cm t/s 2) The iron ball: a) Measure the time duration for 5 periods of the torsional pendulum with the object iron ball t. So the period: T=-t, Here, the To should be measured again with the small holder only. b) The theoretical equation for the moment of inertia of a ball is /,==mr". Carry out the similar evaluation as above Data table no 4: No. 1 2 3 Average y s to(5×Tos 3) The long-thin metal bar(Optional) Data table no 5: 2 3 Average cm s l/c 4. Verify the parallel axis theorem(Optional) Please design a lab to verify the parallel axis theorem experimentally Hints: Draw a diagram for T versus mdr+md2. Try to derive the Kvalue from the slope and understand the meaning of cross-section point between the obtained line and the y-axis Data table no 6:11 metal barrel t. So the period: 1 5 T t  . The previously measured T0 can be used again. b) The theoretical equation for the moment of inertia of a barrel is 2 2 1 2 1 ( ) 8 t I m D D   . Calculate the experimentally measured value I and the theoretical value It. Calculate the percentage difference between them. Data table No. 3: 2) The iron ball: a) Measure the time duration for 5 periods of the torsional pendulum with the object iron ball t. So the period: 1 5 T t  . Here, the T0 should be measured again with the small holder only. b) The theoretical equation for the moment of inertia of a ball is 2 5 2 I mr t  . Carry out the similar evaluation as above. Data table No. 4: No. 1 2 3 Average D / cm t/ s t0 (5T0)/ s m / g 3) The long-thin metal bar(Optional): Data table No. 5: No. 1 2 3 Average D / cm t/ s t0 (5T0)/ s m / g l / cm 4. Verify the parallel axis theorem (Optional) Please design a lab to verify the parallel axis theorem experimentally. Hints: Draw a diagram for T 2 versus m1d1 2 +m2d2 2 . Try to derive the K' value from the slope and understand the meaning of cross-section point between the obtained line and the Y-axis. Mass m1 = g、m2 = g. Data table No. 6: No. 1 2 3 Average Inner diameter D1/ cm Outer diameter D2/ cm t / s m / g