Assuming, hypothetically, that the string had no elasticity. Would the force of the string being pulled travel along the string instantly? Or would there be a time delay?
-
In every "solid" the mechanism for transmission of force is as follows.
A force is applied to an atom at one end. this force accelerates this atom which moves closer to the next atom causing a force.
This force gradually accelerates the second atom until it too has moved towards a third.
In each case the force must firstly accelerate an atom until it moves.
( this is slightly simplified of course but is a fair description of the process)
Now all of this is the condition for a wavespeed.
i.e in any and all solid materials there is a speed of transmission of a wave and hence a time delay between applying a force and having that force appear at the other end.
This applies just as much to a wooden table, a brick wall or a steel rod as it does to string.
The wave speed in string is usually lower than the speed of sound in air.
You can easily see this by stretching a long string and plucking it. You can then watch the wave move along the string, reach the far end then reflect ( upside down of course) and return back to you.
A force is applied to an atom at one end. this force accelerates this atom which moves closer to the next atom causing a force.
This force gradually accelerates the second atom until it too has moved towards a third.
In each case the force must firstly accelerate an atom until it moves.
( this is slightly simplified of course but is a fair description of the process)
Now all of this is the condition for a wavespeed.
i.e in any and all solid materials there is a speed of transmission of a wave and hence a time delay between applying a force and having that force appear at the other end.
This applies just as much to a wooden table, a brick wall or a steel rod as it does to string.
The wave speed in string is usually lower than the speed of sound in air.
You can easily see this by stretching a long string and plucking it. You can then watch the wave move along the string, reach the far end then reflect ( upside down of course) and return back to you.
-
Old Pilot is right, relativity and perfectly inelastic string can not logically co-exist. Information can not be transmitted at greater than the speed of light
How about if it was a light switch with a wire 1 light second long? How long would the light take to come on?
You might be interested in the relativistic spinning disk paradox too
How about if it was a light switch with a wire 1 light second long? How long would the light take to come on?
You might be interested in the relativistic spinning disk paradox too
-
You have several excellent answers, so I will add:
Given that ostriches, penguins, and emus have wings, hypothetically, if a pig had wings, could it fly?
Hypothetically questions that have no basis in the real world, are really meaningless. There is no such thing as a perfectly inelastic material, so conjecturing that such a material exists makes the question meaningless.
Given that ostriches, penguins, and emus have wings, hypothetically, if a pig had wings, could it fly?
Hypothetically questions that have no basis in the real world, are really meaningless. There is no such thing as a perfectly inelastic material, so conjecturing that such a material exists makes the question meaningless.