You can calculate escape velocities
by using the conservation of energy. In other words,
we need to
realize that the kinetic energy needed to escape
has to be equal to the gravitational
potential energy.

Given that
GMm
Gravitational P.E. = -----
r
mv^{2}
Kinetic Energy = -----
2
then
------
/ 2GM
v = / -----
\/ r

Where
**G** is the universal gravitational constant
(6.67 * 10^{-11}
m^{3} / kg * s^{2}), **M** is the
mass of the body and **r** is that body's radius.
The escape velocity
for different planets in the solar system
are approximately:

Mercury: 4.25 km/s

Venus: 10.36 km/s

Earth: 11.18 km/s

Mars: 5.02 km/s

Jupiter: 59.64 km/s

Saturn: 35.41 km/s

Uranus: 21.41 km/s

Neptune: 23.52 km/s

Pluto: 1.00 km/s