In figure (a) and (b) shown the mass M is very large and exerts a gravitational force on ${\mathrm{m}}_1$ and ${\mathrm{m}}_2$. Gravitational force between ${\mathrm{m}}_1$ and ${\mathrm{m}}_2$is very small as compared to that of M. Net force ${\stackrel{\rightharpoonup }{F}}_{net}$ on ${\mathrm{m}}_1$ in accelerating reference frame of ${\mathrm{m}}_2$ is called tidal force. If ${\mathrm{m}}_1$  is to be at rest in reference frame of
${\mathrm{m}}_2$  an additional force equal to tidal force is to be applied on ${\mathrm{m}}_1$. Mark the correct statement(s) using appropriate approximation: