A particle of mass `20 g` is released with an initial velocity `5m//s` along the curve from the point A, as shown in the figure. The point A is at height h from point B. The particle slides along the frictionless surface. When the particle reaches point B, its angular momentum about O will be : (Take `g=10m//s^2`).

Options

A. 6 kg`-m^(2)//s`
B. `3kg -m^(2)//s`
C. `8kg- m^(2)//s`
D. `2kg- m^(2)`

Answer

A

Explanation

`mgh =1/2mv_(B)^(2) -1/2mv_(A)^(2)`
`rArr V_(B) =15 m//s`
`=mV_(B) (OB) =(20/1000 kg)(15 m //s)(20 m) = 6 kgm^(2)//s`.