A ball pushed from a tower with a certain horizontal velocity v0 will land at a point A under the influence of the Earth's gravitational force. If a ball is pushed with higher horizontal velocity, it will land further, at point B. With a further increase in velocity, it will go farther than point B and land at point C. However, at a certain critical velocity vc, it will follow a perfectly circular orbit around the Earth. If the velocity increases above the critical value, the ball will follow an elliptical orbit. Therefore, if a satellite orbits the Earth with critical velocity, it will follow a perfectly circular path around the Earth, under the influence of the Earth's gravitational force. Hence, the centripetal acceleration of a satellite would be equal to its acceleration due to gravity. Substituting for gravitational acceleration and rearranging the terms, the critical velocity of a satellite equals the square root of the product of the gravitational constant and the Earth’s mass divided by its total distance from the Earth's center.