A particle of mass 200 g , is whirled into a vertical circle of radius 80 cm uisig a massless string The speed of the particle when the string makes an angle of `60^(@)` with the vertical line is `1.5ms^(-1).` The tension in the string at this position is

Options

A. 2 mg
B. mg
C. 3 mg
D. `sqrt3mg`

Answer

A

Explanation

When body is released from the position p (inclined at angle `theta` from vertical), then velocity at mean positon
`v=sqrt(2gl(1-costheta))`
`therefore"Tension at the lowest point = mg"+(mv^(2))/(l)`
`=mg+(m)/(l)[2gl(1-cos60^(@))]=mg+mg=2mg`