The radius of earth is about $6400\; km$ and that of mars is $3200\; km$. The mass of the earth is about $10$ times mass of mars. An object weighs $200 \;N$ on the surface of earth. Its weight on the surface of mars will be .......... $N$
$80$
$20$
$6$
$40$
Which of the following symptoms is likely to afflict an astronaut in space $(a)$ swollen feet, $(b)$ swollen face, $(c)$ headache, $(d)$ orientational problem.
Define acceleration due to gravity. Give the magnitude of $g$ on the surface of earth.
If $R$ is the radius of the earth and $g$ the acceleration due to gravity on the earth's surface, the mean density of the earth is
The radii of two planets are respectively ${R_1}$ and ${R_2}$ and their densities are respectively ${\rho _1}$ and ${\rho _2}$. The ratio of the accelerations due to gravity at their surfaces is
The height ${ }^{\prime} h ^{\prime}$ at which the weight of a body will be the same as that at the same depth $'h'$ from the surface of the earth is (Radius of the earth is $R$ and effect of the rotation of the earth is neglected):