A planet is revolving around the Sun in an elliptical orbit. Its closest distance from the Sun is `r` and farthest distance is `R`. If the orbital velocity of the planet closest to the Sun is `v`, then what is the velocity at the farthest point?

Options

A. 20 `kms^(-1)`
B. 15 `kms^(-1)`
C. 10 `kms^(-1)`
D. 16 `kms^(-1)`

Explanation

Let the mass of the planet is m
`r_(1)=0.5xx10^(15) m V_(1)=?`
`r_(1)=1.5xx10^(15) m V_(2)=5kms^(-1)`
According to the kepler second law
`1/2` rv= constant
`rarr r_(1)v_(1)=v_(2)r_(2)`
`therefore v+_(1)=(v_(2)r_(2))/(r_(1))=(5xx1.5xx10^(15))/(0.5xx10^(15))`
`=15 kms^(-1)`