A stone is projected with speed u and angle of projection is `theta`. Find radius of curvature at t=0.

Options

A. `(u^(2) cos^(2) theta)/g`
B. `(u^(2))/(g sin theta)`
C. `(u^(2))/(g cos theta)`
D. `(u^(2) sin^(2) theta)/g`

Answer

C

Explanation

At t=0
`a_(bot)=g cos theta`,
`R=(v^(2))/(a_(bot))=(u^(2))/(g cos theta)`