Question

answer pls the given answer to the question is option b pls tell Me the method

Answer 1

Hey

Assume the following notations ( so that you dont have trouble solving your problem neat ) ^_^

[tex]Mass \ of \ object = m_o \\ We \ know \ m_o*g_e = \frac{Gm_om_e}{R_e^2} ---- \ \ (i)\\ ---\ \textgreater \ m_o * g_m = \frac{Gm_om_m}{R_m^2} ----- \ \ ( ii ) \\ \\ Dividing \ ( i ) \ from \ ( ii ) \ and \ ATQ , \\ \\ --\ \textgreater \ \frac{g_e}{g_m} = \frac{m_e*R_m^2}{m_m*R_e^2} \\ -- \ 6 m_m = R_m^2 * ( \frac{m_e}{R_e^2} ) ---- \ \ ( iii )[/tex]

Now, we have [tex]g_e = \frac{G*m_e}{R_e^2} \\ \\ -\ \textgreater \ \frac{m_e}{R_e^2} = \frac{g_e}{G} \\ \\ We \ replace \ this \ and \ the \ value \ of \ radius \ of \ moon \ in \ eqn. \ ( iii )-\ \textgreater \ \\ \\ 6m_m = 1.738 * 10^6 * 1.738 * 10^6 * \frac{9.8}{6.67 * 10^{-11}} \\ \\ m_m = 7.4 * 10^{22} kg[/tex]

Hence, mass of moon  = 7.4 * 10^22 kg 
Hope this helps ^_^