If the density of the earth is doubled keeping its radius constant,then the acceleration due to gravity will be........ $m/s^2$. $(g = 9.8\,m/s^2)$

The mass of the moon is $7.34 \times 10^{22} \ kg$ and the radius of the moon is $1.74 \times 10^6 \ m$. The value of gravitational acceleration on the moon will be ....... $N/kg$.

The dependence of acceleration due to gravity $g$ on the distance $r$ from the centre of the earth, assumed to be a sphere of radius $R$ of uniform density, is as shown in which of the following figures?

The angular speed with which the earth would have to rotate about its axis so that a person on the equator would weigh $3/5^{th}$ as much as at present is ($g$ = gravitational acceleration, $R$ = equatorial radius of the earth.)

The weights of an object are measured in a coal mine of depth $h_1$,then at sea level of height $h_2=0$,and lastly at the top of a mountain of height $h_3$ as $W_1, W_2$,and $W_3$ respectively. Which one of the following relations is correct? [$h_1 \ll R, h_3 \ll R, R=$ radius of the earth]

Two planets $A$ and $B$ have densities $\varrho_1$ and $\varrho_2$ and have radii $r_1$ and $r_2$ respectively. The ratio of acceleration due to gravity on $A$ to that of $B$ is: