What is the name of the force?

Question

That stops a spinning disc from dropping flat, some years ago I was rolling a steel disc along it was one metre in dia and ten mil. thick when I wanted to put it down I leaned it a little and gave it a twist and it started to rattle round (like a coin does) I stepped onto the centre of it and it held my weight for about ten seconds before coming to rest, now it's not centrifugal force 'cos it only turned about once, so does it have a name?

Answer 1

It's an inertial force which arises in this case from the conservation of angular momentum. When the disc is rolling, it has angular momentum with a certain magnitude, and a particular direction - it is turning around a horizontal axis. For it to come to rest, the angular momentum has to be transferred by friction to the earth, and if you change the axis, that is equivalent to adding some angular momentum around a different axis, so that added momentum has to be dissipated too. The forces against your feet were caused by the disc trying to transfer some its angular momentum to you, probably not very effectively.

Answer 2

It's not a force (and neither is centrifugal force a force) What it is, is simply conservation of angular momentum. The forces involved in the "experiment" you described are gravity (your weight and the disc's) and electromagnetic (the reason the disc does not go through the ground or you through the disc, and the one causing friction)

-jose-

Answer 3

gyroscopic force, based on the principal of conservation of angular momentum.

Answer 4

Inertial force
Its the fifth fundamental force of nature which has so long been neglected .

Answer 5

its centrifrugal foce that moves it a think even though it only spinned once