Question : Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will
a) move towards each other.
b) move away from each other.
c) will become stationary.
d) keep floating at the same distance between them.
[NEET 2017]
Doubt by Manasvini
Solution :
Prerequisite : What is the source of gravitational force — the answer is the mass and distance of the object from those masses. Here it is written the space is gravitational free because the huge mass objects such as planets and spaceship are very far away so their gravitational force is considered to be zero. But because the two astronauts are there so their mass will also be there. Although their mass is very small so does the gravitational field. It was not prominent in presence of huge objects like planets and spaceship but when nothing is there then this small mass also becomes prominent. Since the gravitational force is always attractive in nature this is why both the astronauts will get attracted to each other.
Proper Answer :
The two astronauts are floating in gravity free space. The only space on the two astronauts is gravitational pull of their masses.
F = Gm1m2/r2
which is always attractive in nature. Hence they move towards each other.
Hence, option a) would be the correct answer.