# Mach's principle in empty universe, centripetal force and violation of Newton's laws of motion [closed]

Questions about Mach's principle and empty universe has been asked many times but nowhere can I find it's cross examination with centripetal force. From my point of view the simple logic of centripedal force disproves Mach's principle.

You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when the stars are whirling? Why should they be dangling freely when the stars don't move?

So let's take and empty universe and put the rotating spheres inside. If Mach's principle was right then the spheres can either rotate or not rotate without any effect on the string, meaning that in empty universe the inertia of the linear motion of the spheres can be changed by the string without generating any centripetal/centrifugal force. This is direct violation of Newton's laws of motion.

An object ... continues to move at a constant velocity, unless acted upon by an external force.

## closed as unclear what you're asking by John Rennie, ACuriousMind♦, Kyle Kanos, Alfred Centauri, JimNov 20 '14 at 14:17

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• My understanding is that Mach's idea is really an outmoded way of thinking. So along those lines, asking this question in the form "Does 'x' disprove something nobody thinks anymore" is tantamount to asking "Don't pictures of the Earth from space disprove a flat Earth?" Well, yes, but it's not a particularly illuminating question. – Sean Nov 20 '14 at 12:52
• What is your question? – Kyle Kanos Nov 20 '14 at 12:55
• I am not a physicist, I was merely reading Wikipedia when I got curious about the absolute rotation question and in there Mach's principle is presented as credible theory, certainly not outmoded like flat Earth. Does that mean that absolute rotation is accepted by mainstream physicists and Mach's principle is considered outmoded? – daniel.sedlacek Nov 20 '14 at 15:29