A very small particle rests on the top of a hemisphere of radius 20 cm. The smallest horizontal velocity to be given to it, if it is to leave the hemisphere without sliding down its surface, taking `g = 9.8 ms^-2`

Options

A. `1.4 ms^-1`
B. `2.4 ms^-1`
C. `0.4 ms^-1`
D. `0.7 ms^-1`

Explanation

`u=0`
Distance travelled,`s=ut+1/2at^2`
Distance travelled in first 2 s
`s_1=ut+1/2at^2`
`x=0xx(2)+1/2xxaxx2^2`
`x=2a`
Distance travelled in next 2s
`s_2=ut+1/2at^2`
`y=[0xx4+1/2xxaxx4^2]-2a`
`y=8a-2a=6a=3x` since,y=nx
`:.n=3`