why cant a flying object just leave the atmosphere at a slower speed? why does it need to achieve ‘escape velocity’? if a rocket goes straight up at 100kmph without stopping, it should escape the atmosphere eventually right?

Question

why cant a flying object just leave the atmosphere at a slower speed? why does it need to achieve ‘escape velocity’? if a rocket goes straight up at 100kmph without stopping, it should escape the atmosphere eventually right?

In: Physics

Answer 1

Yes, if you were going straight up at 100kph with a rocket that had the fuel to do it then you could keep going.

Escape velocity is the velocity you need for unpowered flight to go from the current position to infinity. At the Earth’s surface this is 11kps. Any slower and you’d eventually come back down (this doesn’t take into account getting caught in another body’s gravity such as gravitational interaction with say the Moon).