How Do You Calculate Wave Speed Using the Wave Equation?

In summary: Did you make a mistake in your calculations or substitution?In summary, the conversation is about a question asking for help with solving a wave equation problem. The given wave equation is used to find the speed of a wave, and the person is looking for hints or steps in solving it. They mention taking second derivatives and solving for "V", but have not gotten the same answer as using the equation v = \frac{\omega}{k}.
  • #1
Ishu
27
1
Wave Equation problem..! Help...!

Hi can anyone solve this??
I couldn't figure out how to use it

Question
Use the wave equation to find the speed of wave given by

y(x,t)=(3.00 mm) sin [(4.00/m)x-(7.0/s)t) ]





I guess the wave equation is ,

(d^2y) 1 (d^2y)
------- = ------ -------
(dx^2) v^2 (dt^2)


can anyone solve it step wise?
 
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  • #2
Ishu said:
can anyone solve it step wise?

Not really, no. That's not quite how stuff's done on this forum. You're supposed to do the work yourself.

The wave equation:
[tex]\frac{\partial ^2 y}{\partial x^2} = \frac{1}{v^2}\frac{\partial ^2 y}{\partial t^2}[/tex]

For the given wave, can you solve
[tex]\frac{\partial ^2 y}{\partial x^2}[/tex] and [tex]\frac{\partial ^2 y}{\partial t^2}[/tex] ?
 
  • #3
I mean need some hint...

please I ahve 1 more hrs left
 
  • #4
Am i suppose to t6ake second derivative of whole equation...twice? once with respect to t and again with respect to x?
is that how I am supposed to do?
 
  • #5
Ishu said:
Am i suppose to t6ake second derivative of whole equation...twice? once with respect to t and again with respect to x?
is that how I am supposed to do?
Yep, that's what you're supposed to do.
 
  • #6
that means I am supposed to solve for "V" right?

But the answer I got is not the same as the one I got from V=w/k

??
 
  • #7
Ishu said:
that means I am supposed to solve for "V" right?
But the answer I got is not the same as the one I got from V=w/k
??
It should be the same, as the equation reduces to [tex]v = \frac{\omega}{k}[/tex]
 

Related to How Do You Calculate Wave Speed Using the Wave Equation?

1. How is the wave equation used in science and engineering?

The wave equation is a mathematical model that describes the behavior of waves. It is used in various fields of science and engineering, including physics, acoustics, optics, and electronics. It helps scientists and engineers understand and predict the propagation of waves in different mediums, such as sound waves in air or electromagnetic waves in space.

2. What is the general form of the wave equation?

The general form of the wave equation is ∂²u/∂t² = c²∂²u/∂x², where u is the displacement of the wave, t is time, x is the position, and c is the wave speed. This equation expresses the relationship between the second derivative of the wave with respect to time and the second derivative of the wave with respect to space.

3. How is the wave equation derived?

The wave equation is derived from the fundamental laws of physics, such as the Newton's second law of motion and the conservation of energy. It is also based on the assumptions that waves travel at a constant speed and the medium through which the wave propagates is homogeneous and isotropic.

4. What are the boundary conditions in the wave equation?

The boundary conditions in the wave equation refer to the conditions at the boundaries of the medium where the wave is propagating. These conditions can be either fixed or free, depending on the type of wave and the properties of the medium. For example, a fixed boundary condition means that the wave is reflected back with the same amplitude when it reaches the boundary, while a free boundary condition means that the wave is transmitted without any reflection.

5. How is the wave equation solved?

The wave equation can be solved using various analytical and numerical methods. Analytical solutions involve finding a closed-form expression for the wave function, which is usually only possible for simple cases. Numerical solutions, on the other hand, use computational techniques to approximate the solution for more complex cases. These methods include finite difference, finite element, and spectral methods.

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