The relationship between time taken per oscillation and mass

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SUMMARY

The discussion centers on the relationship between mass and time taken per oscillation in a simple harmonic motion experiment. The participant discovered that when plotting mass against time, the graph becomes linear when time is squared, indicating that mass is proportional to the square of the time period (T²). The mathematical derivation involves angular velocity (w), displacement (x), and the force equation (F = -kx), leading to the conclusion that mass (m) can be expressed as m = kT²/4π², where k is a constant. The participant received feedback on improving notation for clarity in their equations.

PREREQUISITES
  • Understanding of simple harmonic motion principles
  • Familiarity with angular velocity and its relationship to oscillation
  • Knowledge of force equations, specifically F = -kx
  • Basic algebra for manipulating equations and understanding proportional relationships
NEXT STEPS
  • Explore the derivation of the simple harmonic motion equations
  • Learn about the significance of angular displacement in oscillatory systems
  • Investigate the role of constants in physical equations, particularly in harmonic motion
  • Review proper notation in physics to avoid confusion in mathematical expressions
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and oscillatory motion, as well as educators looking to clarify concepts related to simple harmonic motion.

WaterMelllon1
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In an experiment, a ruler is connected to the table and some weights are bounded to one end of the ruler. The ruler is then flicked and the time taken per oscillation is measured.

I have plotted a graph with the data I have collected, with the mass on the y-axis and time on x-axis. The graph produced appears to be a curve. I have tried altering the values on the x-axis; I have squared it, 1 over the square of it, square rooted it, and I found that the graph becomes linear when the values are squared. So the mass should be proportional to 1 over the square of the time taken.

I have tried finding out a mathematical relationship for this, but I am not sure if this is correct or not.

Well, if we make w=angular velocity, then w=θ/t, with θ being angular displacement and t being the time period. Since θ belongs in a circle, then it is safe to say that w=2π/t (?)

Also, if the force of an oscillation is proportional to -displacement (x), then it is true to say that F=-kx, with k being a constant.

Since F also = ma, then ma=-kx.

According the the simple harmonic wave equation for acceleration is a=-xw2sinwt. Since the formula for displacement(x) = x sinwt and a=-w2(x sinwt), then a=-xw2

So ma=-kx will become m(-xw2)=-kx, then using some algebra, m=k/w2. Since w=2π/t, then m=kT2/4π2.

Since k/4π2 is a constant, I can ignore that and say m is proportional to t2.

Is my reasoning true? I feel like I am wrong in quite a few spots.

Thanks for helping
 
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Yes, this is essentially correct, but you take a few confusing steps because of a poor choice of notation. For instance, you use x to represent displacement as well as the amplitude (or maximum displacement). You should use different symbols for these - it will help keep things clear for you as well.

You write: x = x sin(wt), which looks nonsensical.

Better would be something like: x = A sin (wt), or x = x0 sin (wt).

Also, next time, a question like this is better suited for the Intro Physics section.
 
Thank you.
 
Yes thank you very much! It is so helpful!
 

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