Does a slinky move up and down equally?

  • Context: High School 
  • Thread starter Thread starter Bagwan
  • Start date Start date
  • Tags Tags
    Slinky
Click For Summary

Discussion Overview

The discussion revolves around the oscillatory motion of a slinky when it is pulled and released. Participants explore whether the distance the slinky moves downward is equal to the distance it moves back upward, considering various initial conditions and definitions of equilibrium.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that the equality of the downward and upward distances depends on initial conditions and the definition of equilibrium.
  • One participant emphasizes the need to clarify how the slinky is pulled and what is meant by equilibrium, noting that different oscillation modes may be excited.
  • A hypothetical scenario is presented where a slinky is pulled down 10 centimeters from its resting position, questioning if it would return the same distance upward.
  • Another participant argues that if the upward distance were not less than the downward distance, the slinky would continue to bounce indefinitely.
  • There is a consideration that if the slinky is lifted and released, it might travel further downward depending on its elasticity and mass.
  • One participant questions why a non-linear spring should not go higher above equilibrium than it was pulled below it, suggesting a potential asymmetry in the motion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the distances are equal, with multiple competing views and uncertainties remaining regarding the conditions affecting the motion of the slinky.

Contextual Notes

Participants mention various factors such as the method of pulling, the definition of equilibrium, and the potential for multiple oscillation modes, which complicate the analysis of the slinky's motion.

Bagwan
Messages
6
Reaction score
0
Let's say there is a slinky being held up. If I pull the bottom of the slinky, it will keep oscillating/vibrating/swinging up and down continuously, until it comes to a stop.

My question is, is the distance the slinky moves down the first time EQUAL to the distance it moves back upwards?

Or is one distance larger than the other?

Thank you very much in advance.
 
Physics news on Phys.org
This depends on your exact initial conditions and what you mean by equal distance (the center of mass displacement from its equilibrium or perhaps the endpoint position).
 
The reference point I'm talking about is the equilibrium, sorry I didn't mention that! At first, the slinky would be at its rest position, then pulled slightly to the bottom.
 
You need to specify exactly how it is pulled (is it pulled down and released from rest, is it just given some momentum, etc).

What do you mean with resprct to the equilibrium? The position of the end? The position of the center of mass of the slinky? Something else?

Regardless of the setup, the answer is likely that it is not going to go up and down equally as you are likely to excite more than one oscillation mode.
 
Purely theoretically, if I were to allow a hanging slinky to reach its resting position (that is, the location where the slinky doesn't move at all while hanging), and then my hand pulled the bottom of the slinky downwards towards the ground slightly (perhaps 10 centimeters below the resting position), if there were a magical ruler that measured the distance it pushed back upwards from the resting position, would that also be 10 centimeters?
 
If it wasn't less, it would keep bouncing indefinitely.
 
Yeah you're right about that, but I was just thinking that they both could be equal, and then in the next oscillation both distances could go down by the same amount. That would still lead it to stopping, right?
 
Now in the other direction would be a different story, if you lifted the end of the coil 10 cm and let it accelerate towards the ground it might travel further depending on its elasticity versus mass.
 
jerromyjon said:
If it wasn't less, it would keep bouncing indefinitely.
He isn't asking about more extension after a full cycle, just after half the cycle. Why shouldn't a non-linear spring, go higher above the equilibrium than it was pulled below it?
 

Similar threads

  • · Replies 50 ·
2
Replies
50
Views
14K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 13 ·
Replies
13
Views
7K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K