A `1kg` stone at the end of `1m` long string is whirled in a vertical circle at a constant speed of `4m//s`. The tension in the string is `6N`, when the stone is at `(g=10m//s^(2))`

Options

A. top of the circle
B. bottom of the circle
C. half way down
D. non of the above

Answer

A

Explanation

`mg=1xx10=10N,(mv^(2))/(r)=(1xx(4)^(2))/(1)=16`
Tension at the top of circle `=mv^(2)/(r)=mg=6N`
Tension at the bottom of circle `(mv^(2))/(r)+mg=26N`