In the experiment to find moment of inertia of flywheel why is the string wound uniformly around the axle?

Answer 1

any discrepancies in spacing between the individual coils would make the experiment inaccuarte. this is because with each rotation of the axle the exact amount of string is uncoiled. if there is a space an uneven amount of string is uncoiled e.g

normal spacing;

------IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII------
(with each rotation, one circumference length of string is uncoiled)

uneven spacing;

-----IIIIIIIIIIIIIII//IIIIIIIIIIIIIIIIIIIIIIIII-------
(with each rotaion, not all the coils are released evenly)

the question is then why does this make it inaccurate? the answer is because the speed of the string uncoiling from the axel is constant in the first example. in the second example it is not. although only slightly different, it effects both uncoiling speed and rate of axel rotation. hope this helps.

Regards Prof Barilli

Answer 2

So it will provide a constant, uniform torque.


Doug