Escape Velocity

The earth is assumed to be a sphere of radius . A platform is arranged at a height from the surface of the earth. The escape velocity of a body from this platform is , where is its escape velocity from the surface of the earth. The value of is:
1.
2.
3.
4.

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

A particle of mass is projected with a velocity, from the surface of the earth. The maximum height, above the surface, reached by the particle is:
(Where escape velocity, the radius of the earth)