A car is moving uniformly along a circle orf raidus `25Csqrt(3)` meter with a time period of 20seconds. A stone is thrown from the car such that it again lands on the car when the car is at a diametricaly opposite point in the orbit. The angle of projection of the stone as seen from the ground should be: (Take `g=10m//s^(2)`)

Options

A. `45^(@)`
B. `60^(@)`
C. `30^(@)`
D. none of these

Explanation

Let T be the time of flight and u be the initial velocity of the stone then:
`2R=(u^(2)sin 2 theta)/(g)` . … (i)
and `T=(2u sin theta)/(g)` … .(ii)
eliminating u, we get
`tan theta=(gT^(2))/(4R)=(10xx10^(2))/(4xx250sqrt(3))=(1)/sqrt(3)`
`rArr theta=30^(@)`