Two very small balls `A` and `B` of masses `4.0kg` and `5.0kg` are affixed to the ends of a light inextensible cord that passes through a frictionless ring of radius negligible compared to the length of the cord. The ring is fixed at some height above the ground . Ball `A` is pulled aside and given a horizontal velocity so that it stars moving on a circular path parallel to the ground, keeping ball `B` in euilibrium as shown. speed of the ball `A` is closest to

Options

A. `2.5m//s`
B. `3.0m//s`
C. `4.0m//s`
D. More information is required to decide.

Answer

B

Explanation

`Tcostheta=m_(A)g` and `T=m_(B)grArrtheta=37^(@)`
and `(m_(A)v_(A)^(2))/(r-2sintheta)=TsinthetarArrv_(A)=3m//s`