Download Weightlessness and apparent weightlessness

Weightlessness and apparent
weightlessness
Astronauts in orbit around the Earth experience what is known as apparent
weightlessness. This is because they are falling towards the Earth at exactly the same
rate as their spacecraft. The same phenomenon is possible for short periods of time in
aircraft “falling” out of certain loop manoeuvres. Relative to their surroundings, an
observer will seem to have no weight. In fact, a weight force is acting on them and
causing them to accelerate. True weightlessness would occur at a point in the universe
where the net gravitational force is zero.
The force of gravity on the Earth’s surface is given by mg. This is sometimes
referred to simply as 1 g. Weightlessness is 0 g. An acceleration or deceleration on a
body which doubles its weight is 2 g, a tripling of weight is 3 g, and so on. Accelerating
feet first is more dangerous, as it causes blood to rush to the head of person and may
burst blood vessels inside the eye or brain.1
Solving problems relating to apparent weightlessness
 Keep in mind Newton’s 3 Laws of motion, particularly F = ma
1. Asimov, I., Asimov’s New Guide To Science, Penguin Books, 1987, p749