Pushing a stick thought experiment

AI Thread Summary
The "pushing a stick" thought experiment explores how long it takes for the other end of a stick, hypothetically stretching from Earth to the sun, to move when one end is pushed. The discussion highlights that the mechanical impulse travels through the stick at the speed of sound in the material, which is significantly slower than the speed of light. It is clarified that if the stick were made of air, the time for movement would be even longer than 15 years, but since sticks are solid, the transmission speed is much faster. Participants emphasize the importance of understanding material properties in this context. Overall, the thought experiment illustrates fundamental principles of physics regarding force transmission in solids.
amentac
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"Pushing a stick" thought experiment

Hello, I'm new here and I wanted to ask a question that has been bugging me for a while. I did a quick search in the forum but frankly not sure what to search for.

Imagine you have a long stick that stretches from the Earth to the sun. If I push on one end of the stick how long will it take for the other end to move?

So more specifically, if the atoms at the end of my finger are pushing on the atoms at one end of the stick and there is lots of space between the atoms, then something is transmitting the pushing action between the atoms. Since nothing travels faster than the speed of light it should take approx 8 min for the other end of the stick to move. If the other end of the stick moves instantaneously then is there something that does travel faster than the speed of light?

tnx
 
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thank you...much longer than 8min
 


amentac said:
thank you...much longer than 8min

Yes, sounds goes about 700 mph, so it would take about 15 years
 


phinds said:
Yes, sounds goes about 700 mph, so it would take about 15 years

In air. In the stick it will be much faster.
 


Lsos said:
In air. In the stick it will be much faster.

DOH !

It's early. My brain is not connected yet. I should keep my mouth shut. Forget I said anything. I'm not even here.
 


Coffee! Drink lots of Coffee!

(I once had a student stop me as I was leaving my office to get my morning coffee. After going over her work for a time (I thought I was being very nice and polite) she said "Please go get your coffee. I can wait."!)
 


Lsos said:
In air. In the stick it will be much faster.

If the stick were made of air it would actually take longer than 15 years for the stick to move. But sticks are not made of air as far as I know.

I have not had coffee. So I am going back to sleep.
 


HallsofIvy said:
Coffee! Drink lots of Coffee!
Brewing a second pot right now!
 

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