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
Escape velocity is what is needed for an object that goes up to keep going up.
The problem with a rocket going straight up at 100 kph and just maintaining that is that you will end up running out of fuel before the earth runs out of gravity. If you were to create a better, more efficient propulsion system then you would eventually get far enough away at just 100 kph you would no longer fall back down and continue outwards.
So its not that it can’t work, its just that we don’t have the technology or capability at this point to make it work.
Remember, gravity is supplying a constant acceleration down towards earth. The farther you get from earth the lower that acceleration is.
Escape velocity is a concept that basically says “If I start at this point going at speed x straight up, I will move so far away from the planet that gravity will never reduce my outward velocity to 0.”
Most of our rocket launches aren’t concerned with reaching an escape velocity, they want orbital velocity. We don’t send many things away compared to what we want to stay nearby.
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