Elevo

Meet Elevo, a bathroom scale riding in a lift who reads a different number every time the doors close.

A scale does not measure your weight directly. It measures how hard the floor has to push up on you, the normal force N. Standing still, that push just balances gravity, so N = mg.

When the lift speeds up going upward, the floor must push harder than gravity to give you that extra acceleration a. Newton's second law then gives N = m(g + a). A 60 kg person in a lift accelerating upward at 2 m/s² reads about 72 kg, not 60.

Speeding up on the way down, or slowing down on the way up, makes a negative and the reading drops. If the cable snapped, a would equal minus g, the scale would read zero, and you would float in free fall.

Astronauts on the space station feel weightless for exactly this reason. They are not beyond gravity. They and their station are falling together around the Earth.