Question

The reason an astronaut in an earth satellite feels weightless is that 

A) this is a psychological effect associated with rapid motion. 

B) the astronaut's acceleration is zero. 

C) the astronaut is beyond the range of the earth's gravity.

 D) the astronaut is falling. 

E) the astronaut is at a point in space where the effects of the moon's gravity and the earth's gravity cancel.

Answer 1

(D)

The weightlessness experienced by an astronaut in a satellite is due to the fact that earth is pulling the astrounaut along with the satellite. So the astronaut is freely falling under the action of gravitational force of the earth. All other options do not apply because the gravitational force is a long range force, the satellite revolves very close to the surface of the earth where it actually feels the gravity.

Now the question arises why doesn't the satellite hit the surface back as soon as it is launched in space. The reason is while a satellite is launched, it is launched with a velocity in the tangential direction and the velocity is so high that the centripetal force balances the gravity.