Answer to Question #1381 in Astronomy | Astrophysics for chucky

Question

In order to escape a planet's orbit, an object must

Answer 1

The object must have the velocity at which the sum of kinetic and its gravitational potential energy is equal to zero (escape velocity).
Thus
mv²/2 - G mM/R = 0, where G - is gravitational constant, M - the mass of the planet, R - is the orbit of the moving object, m - is the mass of the object.

v = √(2GM/R)