Escape velocity

If a cannon ball was just to escape from the surface of the Earth to infinity, the initial kinetic energy would be equal to the potential energy lost if it were to be 'dropped' from infinity (the zero of PE) to the surface of the Earth.

Escape velocity is given by ...

... where the symbols have their usual meanings.

Escape velocity (from Earth) is close to 11,000 m/s. It is not possible to make a gun with a firing chamber strong enough to withstand the nuclear explosion required to put a shell on the Moon.

> More