What is the average energy of a harmonic oscillator with varying periods?

  • Thread starter Lewis
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In summary, the conversation discusses the use of the Simpsons/Trapazoidal rule for calculating the kinetic energy of a harmonic oscillator. It also involves determining the average energy over a period of time for different values of the period and plotting the results. The conversation also addresses the integration of a sine function.
  • #1
Lewis
I believe the following problem involves using the Simpsons/Trapazoidal rule, and I've tried everything and get nowhere but rediculus integrals. Any help would be greatly appreciated.


For the harmonic oscillator, the kinetic energy is:

<K>=(1/T) Integral[0.5 m(x^2), {t, 0, T}] (I hope that's clear, I typed it as I would in mathematica, sort of)

where x is the position. Now if x(t)=5.0Sin[wt] then determine the average energyover a period of time equal to 5 seconds for differing values of the period y, where w=2pi/y . Calculate the average kinetic energy if the mass is 0.100kg and the period y takes on values of 1,2,3,4 and 5 seconds and then plot the average kinetic energy against period.


So in case the t's are confusing, T=5, and the upper limit on the integral would be 5, the lower 0 and the variable of integration would be t. Thanks very much.
 
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  • #2
The integral of sin2 ([itex]\omega[/itex]t) should be straightforward. Squaring the function ensures it is positive and nonzero.
 
  • #3
Okay, I see now. Thank you.
 

What is the Simpsons Rule?

The Simpsons Rule, also known as the Composite Simpson's Rule, is a method of numerical integration used to approximate the value of a definite integral. It is based on using quadratic polynomials to approximate the curve of the function being integrated.

What is the Trapazoidal Rule?

The Trapazoidal Rule is another method of numerical integration used to approximate the value of a definite integral. It is based on approximating the curve of the function with straight line segments, or trapezoids, and finding the area under these segments.

What is the difference between Simpsons and Trapazoidal rule?

The main difference between the Simpsons Rule and the Trapazoidal Rule is that the Simpsons Rule uses quadratic polynomials to approximate the curve of the function, while the Trapazoidal Rule uses straight line segments. This means that the Simpsons Rule is generally more accurate and provides a better approximation of the integral.

When should I use Simpsons Rule over Trapazoidal Rule?

It is generally recommended to use the Simpsons Rule over the Trapazoidal Rule when the function being integrated is smooth and does not have any sharp changes or corners. This is because the Simpsons Rule is more accurate and provides a better approximation in these cases.

How do I calculate the error in Simpsons and Trapazoidal rule?

The error in Simpsons and Trapazoidal rule can be calculated by using the error formula for each method. For Simpsons Rule, the error formula is E = (-1/90) * h^5 * f''''(c), where h is the step size and f''''(c) is the fourth derivative of the function being integrated. For Trapazoidal Rule, the error formula is E = (-1/12) * h^3 * f''(c), where h is the step size and f''(c) is the second derivative of the function being integrated.

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