Weightlessness

The concept ofweightlessnessis one that is easily misunderstood by most people until they have been exposed to introductory physics for the first time. For example, many of us learn early on (correctly) that weight depends on force of gravityFg=mg, and that we weigh more on earth than on the moon because the strength of gravity on earth (g=9.8 m/s2) is greater than that of the moon (g=1.6 m/s2). It's no surprise, then, that one common misconception is that an object becomes weightless when the force of gravity becomes equal to zero. Strictly speaking, this statement would be true if not for the fact that the force of gravity can never be exactly equal to zero (see thelesson on gravitationfor more details about the formula for the force of gravity). This is because gravity has an effect even over incredibly long distances, despite the fact that it is the weakest of the fundamental forces.

Examples :

Astronauts on the International Space Station experience onlymicrogravityand thus display anexample of weightlessness. ... The block is said to be in a state ofweightlessnessalthough being pulled down by the planet's gravity.