Why is it more difficult to revolve a stone tied to a longer string than a stone tied to a shorter string ?

Explanation

MI of stone I ` = ml^2 ( l to " length of string")` l is larger , `alpha ` is very small
` tau = I alpha`
`alpha = tau /I = (tau)/(ml^2)`
If l is larger `alpha ` is very small
` therefore ` more difficult to revolve .