27. What is an escape velocity? (A K2S Question)

From The Space Library

Escape velocity is the minimum velocity required to depart the gravitational field of an astronomical body. Imagine a rocket is launched straight up from Earth. As it goes up the booster eventually burns out and the rocket begins to coast. Since the Earth's gravity exerts a downward force on the rocket, it begins to slow down. But the farther the rocket gets from Earth, the less gravity there is. Consequently, if the rocket is going at great enough velocity at burnout, it will keep slowing down but it will never actually stop and fall back to Earth. That velocity is escape velocity and for Earth it is about 25,000 miles per hour or about 36,000 feet per second. (Ref. 6)

6.Faget, Max. Manned Space Flight. Holt, Rinehart, and Winston, New York, 1965.

Answer provided by Jon H. Brown

Question and Answer extracted from the book Kids to Space - by Lonnie Schorer