A double star consists of two stars having masses `M` and `2M`. The distance between their centres is equal to `r`. They revolve under their mutual gravitational interaction. Then, which of the following statements are not correct?

Options

A. `r^(3/2)`
B. `r`
C. `m^(1/2)`
D. `m^(-1/2)`

Answer

A, D

Explanation

`r_(2)=(2mr)/(m+2m)=(2r)/3`
`T_(2)^(2)=(4pi^(2)r_(2)^(2))/(GM)impliesT_(2)^(2)=(32pi^(2)r^(3))/(27Gm)`
`T_(2)propr_(2)^(2)` and `T_(2)propm^(1/2)`