The mass of the earth is 6.00 ×10^24 kg an

Your Ultimate Guide to JEE & NEET Question Solutions

The mass of the earth is $6.00 \times {10^{24}}\,kg$ and that of the moon is $7.40 \times {10^{22}}\,kg$. The constant of gravitation $G = 6.67 \times {10^{ - 11}}\,N - {m^2}/k{g^2}$. The potential energy of the system is $ - 7.79 \times {10^{28}}\,joules$. The mean distance between the earth and moon is

A

$3.80 \times {10^8}\,metres$

B

$3.37 \times {10^6}\,metres$

C

$7.60 \times {10^4}\,metres$

D

$1.90 \times {10^2}\,metres$

The mass of the earth is $6.00 \times {10^{24}}\,kg$ and that of the moon is $7.40 \times {10^{22}}\,kg$. The constant of gravitation $G = 6.67 \times {10^{ - 11}}\,N - {m^2}/k{g^2}$. The potential energy of the system is $ - 7.79 \times {10^{28}}\,joules$. The mean distance between the earth and moon is

$U = - \frac{{GMm}}{r}$

$ \Rightarrow \,7.79 \times {10^{28}} = \frac{{6.67 \times {{10}^{ - 11}} \times 7.4 \times {{10}^{22}} \times 6 \times {{10}^{24}}}}{r}$

$ \Rightarrow \,\,r = 3.8 \times {10^8}\,m$