The ratio of the time taken by a solid sphere and that taken by a disc of the same mass and radius to roll down a smooth inclined plane from rest from the same height -

Options

A. `15:14`
B. `sqrt15 : sqrt14`
C. `14:15`
D. `sqrt14 : sqrt15`

Answer

D

Explanation

`t=sqrt((2s)/("g"sin theta)(1+(K^(2))/R^(2)))`
`t_(1)/r_(2)=sqrt((1+2/5)/(1+1/2))=sqrt(14/15)`