Question

why do astronauts on the internation space station (iss) experience weightlessness?
because there is no gravity in space. since there is no gravity, they have no weight.
because they are orbiting earth and anything that is in orbit is in free fall.
because of the tidal influence of the moon.
because they have no mass in space. if there is no mass, there is no weight.
because this past fiscal year they itemized their deductions and as a result were able to completely eliminate their weight.
because the food on the iss sucks.

Explanation:

• Option 1: Gravity exists in space. The ISS is within Earth's gravitational field.
• Option 2: Objects in orbit are in a state of free - fall. The ISS is in orbit around Earth, and the astronauts inside are also in free - fall. In free - fall, the normal force (which we perceive as weight) is zero.
• Option 3: The tidal influence of the Moon is a very small effect compared to the orbital motion of the ISS and is not the cause of weightlessness on the ISS.
• Option 4: Mass is an intrinsic property of an object and does not change in space.
• Option 5: Tax deductions have nothing to do with physical weight.
• Option 6: The quality of food has no relation to the physical phenomenon of weightlessness.

Answer:

Because they are orbiting Earth and anything that is in orbit is in free fall.