The gravitational potential energy of a rocket of mass 100 kg at a distance `10^(7)` m from earth is `-4xx10^(9)J`. Then its weight in N at `10^(9)m` is

Options

A. `8xx10^(-2)`
B. `8xx10^(-3)`
C. `4xx10^(-3)`
D. `4xx10^(-2)`

Answer

d

Explanation

`"P.E. "=("GMm")/(r)`
`therefore" GMm"=rxxP.E.`
`=4xx10^(16)`
`F=("GMm")/(r^(2))=4xx10^(16)xx10^(-18)`
`=4xx10^(-2)`