If the angular velocity of earth's spin is increased such that the bodies at the equator start floating, the duration of the day would be approximately ........ minutes

(Take : $g =10 \,ms ^{-2},$ the radius of earth, $R =6400 \times 10^{3}\, m ,$ Take $\left.\pi=3.14\right)$

The mass of the earth is $81$ times that of the moon and the radius of the earth is $3.5$ times that of the moon. The ratio of the acceleration due to gravity at the surface of the moon to that at the surface of the earth is

A projectile is fired from the surface of the earth with a velocity of $5\, ms^{-1}$ and angle $\theta$ with the horizontal. Another projectile fired from another planet with a velocity of $3\, ms^{-1}$ at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is (in $ms^{-2}$) is (given $g = 9.8\, m/s^2$)

A body weighs $700 \,gm$ wt on the surface of the earth. How much will it weigh on the surface of a planet whose mass is $\frac{1}{7}$ and radius is half that of the earth ........ $gm\, wt$

The acceleration due to gravity about the earth's surface would be half of its value on the surface of the earth at an altitude of ......... $mile$. ($R = 4000$ mile)

The height at which the weight of a body  becomes ${\frac{1}{16}}^{th}$ , its weight on the surface of earth (radius $R$), is