Question

The distance between earth and moon is `3.8 xx 10^(8)m`. Determine the gravitational potential energy of earth-moon system. Given, mass of the earth `= 6 xx 10^(24) kg`, mass of moon `= 7.4 xx 10^(22)kg` and `G = 6.67 xx 10^(-11) Nm^(2) kg^(-2)`

Answer 1

Here, `r = 3.8 xx 10^(8) m, M_(e) = 6 xx 10^(24) kg, M_(m) = 7.4 xx 10^(22) kg`
The gravitational potential energy of earth-moon system is
`U = (-GM_(e)M_(m))/(r ) = (-(6.67xx 10^(-11))xx (6 xx 10^(24)) xx (7.4 xx 10^(22)))/(3.8 xx 10^(8)) = - 7.78 xx 10^(28) J`