Isn’t going up with velocity greater than 9.81 m/s be enough to escape earth’s gravity?
In: Physics
9.81 m/s² is earth’s gravitational pull at the surface: Every second, the a free falling object accelerates by 9.81 m/s. That is why the unit is meters per second *per second*, not just meters per second.
So each second the spaceship is flying away from earth, it loses some speed. This value drops off as the spaceship moves away from earth, eventually becoming so small that the spaceship is affected stronger by the gravity of the sun than the earth – it is now no longer in earth orbit, but in sun orbit, from where it can move to other planets.
Escape velocity is the speed at which the spaceship is moving fast enough to reach that point without falling back to earth – if the spaceship is shot by a cannon from the surface. Real spaceships however fly in orbits around earth, which makes this a lot more complicated.
If you haven’t heard about it, there’s a great game called Kerbal Space Program, which has a pretty good simulation for orbital mechanics. If you’re interested in the topic, I recommend checking the game out on YouTube.
Latest Answers