Is Additional Speed Beyond Orbital Velocity Needed for Escape?

[menager31]

of course i know how to count thaht but i ve got one question. If something is moving on the orbit with velocity v, and escape velocity is u, then when we want our object to escape , the minimum speed which we must add is u-v ?

 

[hellfire]

You have an object of mass m which has first an orbital velocity Vo (or "v") and an additional velocity V' at a radius R from a mass M, and, afterwards, zero velocity at infinity (R = infinite) escaping from mass M. If you apply energy conservation between (1) and (2) and check against u² = 2GM/R you will find out the answer to your question.

 

[menager31]

i know how to count it but you are thinking about sth else let's say that our mass has got horizontal velocity on the Earth If this velocity is more than escape velocity, will the mass escape?

 

[Janus]

i know how to count it but you are thinking about sth else let's say that our mass has got horizontal velocity on the Earth If this velocity is more than escape velocity, will the mass escape?

Yes, it will.