Question

Why there is no gravity inside Inter National Space Station. But people say Space station is in orbit because of Earths gravitation.

Answer 1

The effective gravity inside the ISS is very close to zero, because the station is in free fall. The effective gravity is a combination of gravity and acceleration.

If you're standing on the surface of the Earth, you feel gravity (1g, 9.8 m/s2) because you're not in free fall. Your feet press down against the ground, and the ground presses up against your feet.

http://physics.stackexchange.com/questions/29929/gravity-on-the-international-space-station

Answer 2

Yes I got You. But ISS is not in free fall but actually its in angular rotation. Is there any similarity between angular rotation and free fall.

Answer 3

you say that something is in free fall if it is experiencing an acceleration towards the earth('s centre to be precise) at an acceleration of g (now remember g need not mean 9.8m/s^2.. thats only near the earth's surface).

so you take drop an object you know its falling towards the earth with acceleration g.. hence its a free fall..

now when you consider space stations orbiting whats providing them the centripetal force?!? the earths gravity.. and hence they also experience an acceleration TOWARDS the earth's centre which is g (at that height, could be way less than 9.8).

so its like this.. the space station is FALLING but at the same time is MOVING away .. so the MOVING away and FALLING balance such that it orbits.. whenever something orbits its in a constant free fall

Answer 4

you guys mean this way i believe.

Answer 5

not necessarily circular orbit but gives you the idea.