Period for real-life spring experiment

In summary, air resistance has a small effect on the period of a spring, which might be due to heat generation or the twisting effect of the mass. Adding a second person to help keep the oscillator in a swinging motion can help maintain a constant period.
  • #1
doppelganger007
18
0
Hi,

I have a question from a lab experiment for an online course. The question states "In a real spring experiment, you wouldn't expect the period predicted by the formula for the period of a harmonic oscillator. What is the reason for this, and the would the actual value be larger or smaller than the predicted one?"

My partner and I initially thought it was air resistance, but we finally concluded that air resistance would not have an affect on the period of the spring. The spring in question is one that is hanging downward with a mass attached to it. Any suggestions? Thanks in advance.
 
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  • #2
Air could have a very small effect on the frequency, making the oscillator behave as a damped oscillator. Some damping could also come from heat generated by flexing the spring. An additional consideration might be the mass of the spring itself. The effects of damping are modeled as a velocity dependent resistance to the motion.

http://hyperphysics.phy-astr.gsu.edu/Hbase/oscda.html
 
  • #3
Thanks OlderDan, now I have another related problem. It asks about why a second grader on a swing who tries to maintain a constant period keeps slowing down. Isn't it then because of damping, as with the spring? And also, what could then be done to "combat" the deceleration and thus maintain a constant period?
 
  • #4
doppelganger007 said:
Thanks OlderDan, now I have another related problem. It asks about why a second grader on a swing who tries to maintain a constant period keeps slowing down. Isn't it then because of damping, as with the spring? And also, what could then be done to "combat" the deceleration and thus maintain a constant period?
For a swing, that cool breeze you feel is in fact always slowing you down. There is also some friction in the pivot points. A second grader might appreciate the help of a friend doing what?
 
  • #5
Real springs do have mass. Also in a real experiment one would expect the up and down motion to include swinging from side to side. How this would actually influence the period is beyond me.
 
  • #6
andrevdh said:
Real springs do have mass. Also in a real experiment one would expect the up and down motion to include swinging from side to side. How this would actually influence the period is beyond me.
Even without the swinging motion, there is a twisting effect. The spring winds and unwinds as it stretches and relaxes. This looks like a nice discussion of the situation, and includes a brief discussion of other two-degree-of freedom systems.

http://online.redwoods.cc.ca.us/instruct/darnold/deproj/sp04/stevemisay/Project1.pdf

Adding your swinging would make it 3-degrees if it stayed in a plane and another if it does not. Messy stuff when all is said and done, but there are simple examples of coupled oscillators where the energy migrates from one mode to another. Two pendula connected by a light spring for example.
 
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Related to Period for real-life spring experiment

What is the purpose of a "Period for real-life spring experiment"?

The purpose of a "Period for real-life spring experiment" is to study the time it takes for a real-life spring system to complete one full oscillation or cycle. This can help us understand the behavior of springs and their applications in various fields such as engineering, physics, and biology.

What materials are needed for a "Period for real-life spring experiment"?

The materials needed for a "Period for real-life spring experiment" include a real-life spring, a stopwatch or timer, a ruler or measuring tape, and a stable surface to attach the spring to. Optional materials may include weights, different types of springs, and a data recording device.

How do you measure the period of a real-life spring experiment?

To measure the period of a real-life spring experiment, start by attaching the spring to a stable surface and measuring its length. Then, pull the spring down and release it, making sure it is not touching anything else. Use a stopwatch or timer to measure the time it takes for the spring to complete one full oscillation. Repeat this process multiple times and calculate the average time to get a more accurate result.

How does the mass of the object affect the period of a real-life spring experiment?

The mass of the object attached to the spring does not affect the period of a real-life spring experiment. According to Hooke's law, the period of a spring is only dependent on its stiffness and the force applied to it, not the mass of the object.

What factors can affect the accuracy of a "Period for real-life spring experiment"?

Some factors that can affect the accuracy of a "Period for real-life spring experiment" include air resistance, friction in the spring, and human reaction time when measuring the period. To minimize these factors, it is important to conduct the experiment in a controlled environment and repeat the measurements multiple times to get an average value.

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