gravitation Questions

The escape velocity from the Earth’s surface is $v$. The escape velocity from the surface of another planet having a radius, four times that of Earth and same mass density is:

If $E$ and $G$ respectively denote energy and gravitational constant, then $E/G$ has dimensions of:

A particle of mass $m$ is projected with a velocity $u=k{v}_e$ ($k<1$) from the surface of the earth ($v_e$ = escape velocity). The maximum height above the surface reached by the particle is: