Vibrating String: Interpreting ∂u/∂x(L,t)=0 Boundary Condition

In summary, the given conversation discusses the physical interpretation of the boundary condition ∂u/∂x(L,t)=0 and how it affects the solution for the given problem of a clamped string. The condition indicates that the string is always perpendicular to the wall at the endpoint, similar to a relaxed string attached to a pole without friction. It is important to understand the meaning of derivatives in the problem and how they affect the solution.
  • #1
prehisto
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Homework Statement



(∂^2 u)/(∂t^2 )=a^2 (∂^2 u)/(∂x^2 ) x∈(0,l) t>0
u(0,t)=0 ; ∂u/∂x(L,t)=0
u(x,o)=u1; ∂u/∂t(x,o)=x

I can not figure out physical interpretation of boundary condition ∂u/∂x(L,t)=0, what does it mean. Can someone can help me with this ?

Homework Equations





The Attempt at a Solution


 
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  • #2
The string is clamped at L and 0. So its amplitude is 0 there.
 
  • #3
That's not true. ∂u/∂x(L,t)=0 means that the string is always perpendicular to the wall at the other endpoint. So you can think a very relaxed string being attached to a pole, sliding along it without friction.
 
  • #4
Thanks.
 
  • #5
One way to understand what is it each time, is:
1. Know what derivatives in your problem mean.
2. See how it affects your solution after you bring them in it.
 

Related to Vibrating String: Interpreting ∂u/∂x(L,t)=0 Boundary Condition

What is a vibrating string?

A vibrating string is a physical system that consists of a string fixed at two ends and set into motion. It is a common model used in physics and engineering to study the behavior of waves and oscillations.

How is the boundary condition defined for a vibrating string?

The boundary condition for a vibrating string is defined as ∂u/∂x(L,t)=0, which means that at the endpoint of the string (x=L), the partial derivative of the displacement (u) with respect to the position (x) is equal to 0. In simpler terms, this means that the endpoint of the string is fixed and does not move.

Why is the boundary condition important for studying a vibrating string?

The boundary condition is important because it helps us understand the behavior of the vibrating string at its endpoints. In real-world scenarios, the endpoints of a string are usually fixed or attached to a larger structure, so understanding how the string behaves at these points is crucial for accurate modeling and predicting its behavior.

How does the boundary condition affect the solution to the vibrating string equation?

The boundary condition affects the solution to the vibrating string equation by limiting the possible solutions to only those that satisfy the condition. This helps us find the specific solution that accurately describes the behavior of the string in a given scenario.

What are some real-world applications of studying vibrating strings?

Vibrating strings have many real-world applications, such as understanding and designing musical instruments, analyzing the behavior of bridges and other structures, and investigating the properties of materials. This model is also used in fields such as acoustics, seismology, and telecommunications.

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