Gravitation doubt

A satellite is orbiting the earth close to the surface...a particle is to be projected from the satellite to just escape from the earth....the escape speed of earth is v....its speed with respect to the satellite will...

A> be less than v
B> be greater than v
C> will be equal to v
D> will depend on the direction of projection

plz explain with reason!!!

thanx!!!

5 Answers

39
Pritish Chakraborty ·

I believe that as the satellite is orbiting the Earth, it has already escaped Earth's gravitational acceleration. Any particle projected from the satellite now should have the satellite's velocity(which is less than escape velocity, escape velocity is only required to escape the earth's gravitational acceleration, not to orbit the earth). I think it will be A).

But my dear friend Tushar is giving complex reasons which amount to the particle's path and its relation to escape velocity, which I fail to understand. In short, as per him the answer is B).

Disclaimer : I am not responsible for the damage my views may cause to you.

1
buddyboyyash ·

i think u did not notice the word "close" in the question..i think it can be considered that satellite is orbiting on the surface of the earth..

now...any particle projected from the satellite with a velocity u (say)

the velocity of that particle will be u + velocity of particle

and for that particle to JUST ESCAPE the earth, u should be greater than v

coz if u = v...that particle will first go in a parabolic path n then leave earth's gravitational field

so the answer according to me is also B

bt to our surprise...the answer is D.....

i dunno how!!!

i hope u understood wat i wanted to say

no need for disclaimer...we all are here to learn!!!

1
buddyboyyash ·

lol...yeah...i do want the explanation!!!..plz!!!

1
buddyboyyash ·

oh k...understood

bt y does it happen that wen we derive an expression for escape velocity of earth...we find that it is independent of direction of projection??

coz satellite is also on earth's surface ryt??....so we can consider that it is being projected from earth...ryt??

i know i m acting foolish...bt plz explain!!!!

1
buddyboyyash ·

oh k...got it

so if the same question wud hav been sumthin like

the particle had to just escape satellite's gravitational field

OR

the particle was projected from the earth

then the answer would be B...ryt??

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