The radii of circular orbits of two satellite `A` and `B` of the earth are `4R` and `R`, respectively. If the speed of satellite `A` is `3v`, then the speed of satellite `B` will be

Options

A. `3v//4`
B. `6v`
C. `12v`
D. `3v//2`

Answer

B

Explanation

Orbital velocity of satellite `v=sqrt((GM)/r)`
`implies (v_(A))/(v_(B))=sqrt((r_(B))/(r_(A)))=sqrt(R/(4R))=1/2`
`:. (v_(A))/(v_(B))=(3v)/(v_(B))=1/2`
` :. v_(B)=6v`