Escape Velocity Definition
When an object reaches the speed that it is capable of breaking the Earth’s gravitational barrier then we say that it is travelling at escape velocity. i.e. Escape velocity is the minimum velocity that when an object travels at that speed can break the gravitational barrier of that celestial body.
The image added below shows a rocket escaping the Earth’s gravitational field, the velocity must be greater than the escape velocity of the Earth for the rocket to leave Earth’s gravitational pull. The satellite revolving around the Earth has a specific velocity that is less than the Escape velocity of the Earth but high enough to provide the satellite with enough energy to revolve around the Earth. If the velocity of the object is less than the orbital velocity of the planet then the object thrown in the atmosphere returns back to the Earth’s surface as the ball thrown by the boy does.
Note: The escape velocity at the Earth’s Surface is 11.2 km/sec.
Escape Velocity
Escape velocity as the name suggests, is the velocity required by an object to escape from the gravitational barrier of any celestial object. “What happens when you throw a stone upward in the air?” The stone comes back to the Earth’s surface. If we throw the stone with a much higher force still it comes back to the Earth’s surface because of the gravitational force of Earth.
What happens when we keep increasing the force the initial velocity of the stone keeps getting higher till it reaches the point when it never comes back to the Earth’s surface. The velocity at this point is called Escape velocity. Let’s learn more about Escape Velocity and others in detail in this article.