If M e is the mass of earth and M m is the mass of moon ( M e=81 M m ). The potential energy of an object of mass m situated at a distance R from the centre of earth and r from the centre of moon, will be :-

Question

If M e is the mass of earth and M m is the mass of moon ( M e=81 M m ). The potential energy of an object of mass m situated at a distance R from the centre of earth and r from the centre of moon, will be :- (A) - GmM m (( R /81)+ r ) (1/ R 2) (B) - GmM e((81/ r )+(1/ R )) (C) -GmM m ((81/ R )+(1/ r )) (D) GmM m ((81/ R )-(1/ r ))

Tardigrade Admin · Accepted Answer

=-(G Me m/R)-(G Mm m/r) =-(G(81 Mm) m/R)-(G Mm m/r) =-G m Mm((81/R)+(1/r))

Q. If $M_{e}$ is the mass of earth and $M_{m}$ is the mass of moon $(M_{e} = 81 M_{m})$ . The potential energy of an object of mass $m$ situated at a distance $R$ from the centre of earth and $r$ from the centre of moon, will be :-

$- G m M_{m} (\frac{R}{81} + r) \frac{1}{R ^{2}}$

$- G m M_{e} (\frac{81}{r} + \frac{1}{R})$

$- G m M_{m} (\frac{81}{R} + \frac{1}{r})$

$G m M_{m} (\frac{81}{R} - \frac{1}{r})$

$= - \frac{G M _{e} m}{R} - \frac{G M _{m} m}{r}$
$= - \frac{G ( 81 M _{m} ) m}{R} - \frac{G M _{m} m}{r}$
$= - G m M_{m} (\frac{81}{R} + \frac{1}{r})$

Q. If Me​ is the mass of earth and Mm​ is the mass of moon (Me​=81Mm​). The potential energy of an object of mass m situated at a distance R from the centre of earth and r from the centre of moon, will be :-

−GmMm​(81R​+r)R21​

−GmMe​(r81​+R1​)

−GmMm​(R81​+r1​)

GmMm​(R81​−r1​)