A rupee coin, starting from rest rolls down a distance of 1 m on a plane inclined at an angle of `30^(@)` with the horizontal. Assuming that `g=9.81 ms^(-2)`, time taken is : -

Options

A. 0.78 s
B. 0.6 s
C. 0.5 s
D. 0.7 s

Answer

A

Explanation

Here, `l=1m, theta 30^(@)`
`g=9.81 ms^(-2), t=?`
`because " "t=sqrt((2l(l+K^(2)//R^(2)))/(g sin theta))`
For a rupee coin, `K^(2)=(1)/(2)R^(2)`
`rArr" "t=sqrt((2xx1(1+1//2))/(9.81 sin 30^(@)))=sqrt((6)/(9.81))=0.78s`