An inclined plane makes an angle `30^(@)` with the horizontal. A groove (OA) of length 5m cut in the plane makes an angle `30^(@)` with OX. A short smooth cylinder is free to slide down under the influence of gravity. The time taken by the cylinder to reach from A to O is `(g=10ms^(-2))`.

Options

A. 4s
B. 2s
C. 3s
D. 1s

Answer

B

Explanation

Acceleration of cylinder down the plane is
`a=(g sin 30^(@))(sin 30^(@))`
`=10((1)/(2))((1)/(2))=2.5 ms^(-2)`
Time taken `t=sqrt((2s)/(a))= sqrt((2 xx 5)/(2.5))=2s`.