If the radius and acceleration due to gravity both are doubled,the escape velocity of the Earth will become ......... $km/s$.

The Earth is assumed to be a sphere of radius $R$. $A$ platform is arranged at a height $R$ from the surface of the Earth. The escape velocity of a body from this platform is $fv$,where $v$ is its escape velocity from the surface of the Earth. The value of $f$ is

$A$ body is projected vertically from earth's surface with $\left(\frac{1}{3}\right)^{\text{rd}}$ of escape velocity. The maximum height reached by the body is ($R=$ radius of earth).

$A$ spaceship moves from the Earth to the Moon and back. The greatest energy required for the spaceship is to overcome the difficulty in:

The potential energy of a satellite is $-8 \times 10^9 \ J$. What is its binding energy (escape energy)?

Escape velocity on a planet is $v_e$. If the radius of the planet remains the same and the mass becomes $4$ times,the escape velocity becomes: