The mass and the diameter of a planet are three times the respective values for the Earth. The period of oscillation of a simple pendulum on the Earth is $2\,s$. The period of oscillation of the same pendulum on the planet would be

If mass of a body is $M$ on the earth surface, then the mass of the same body on the moon surface is

The radii of two planets $A$ and $B$ are $R$ and $4 R$ and their densities are $\rho$ and $\rho / 3$ respectively. The ratio of acceleration due to gravity at their surfaces $\left(g_A: g_B\right)$ will be

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 $\left.\pi=3.14\right)$

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