Therefore \oint_{S}\vec{r}\cdot\vec{n}dS=3V

In summary, the conversation is about a person needing help with a vector calculus problem involving evaluating a closed surface. They are advised to use the divergence theorem and are given the formula to use. The answer is determined to be 3 times the volume of the closed surface.
  • #1
galipop
51
0
Hi All,

I've been working through a series of vector calculus problems and I need some help to get started with this one. Anyone care to help?

The problem is:

Evaluate [tex]\oint_{s} r.n.dS[/tex] where S is a closed surface.

Cheers
 
Physics news on Phys.org
  • #2
What is the meaning of this?
a)[tex]\int_{S}r\vec{n}\cdot{d}\vec{S}[/tex]
b)[tex]\int_{S}\vec{r}\cdot\vec{n}dS[/tex]
 
  • #3
b)

sorry I didn't know how to do the vector symbol.
 
  • #4
Use the divergence theorem:
[tex]\vec{r}=x\vec{i}+y\vec{j}+z\vec{k}[/tex]
Hence, the answer is 3V, where V is the volume.
 
  • #5
Ok I'll give it a try. Hmm I keep noticing the divergence theorem popping up.
 
  • #6
OK then:

[tex]\int_{S}\vec{r}\cdot\vec{n}dS = \int_{V}\nabla\cdot\vec{r}dV[/tex]

Therefore
[tex]\int_{V}\nabla\cdot\vec{r}dV=\int_{V}3dV[/tex]
[tex]=3V[/tex]
 

What is a vector calculus problem?

A vector calculus problem involves the application of vector calculus, which is a branch of mathematics that deals with vectors, vector fields, and their operations. In these types of problems, vectors are used to describe physical quantities such as velocity, force, and acceleration.

What are the key concepts in vector calculus?

The key concepts in vector calculus include vector operations (such as addition, subtraction, and multiplication), vector fields, line and surface integrals, and the gradient, divergence, and curl of a vector field.

How do you solve a vector calculus problem?

To solve a vector calculus problem, you typically start by defining the problem and identifying the known and unknown variables. Then, you use vector operations and concepts to manipulate the given information and solve for the unknown variable. This may involve taking derivatives or integrals, or using geometric properties of vectors.

What are the real-world applications of vector calculus?

Vector calculus has many real-world applications, particularly in physics and engineering. It is used to describe and analyze physical quantities such as motion, forces, and electromagnetic fields. It is also used in fields such as computer graphics, fluid mechanics, and economics.

Are there any common mistakes when solving vector calculus problems?

Yes, there are some common mistakes that can occur when solving vector calculus problems. These include using incorrect vector operations, not properly setting up the problem, and making errors in calculations. It is important to carefully check your work and use proper notation and techniques to avoid these mistakes.

Similar threads

Replies
2
Views
2K
Replies
1
Views
1K
  • Calculus
Replies
1
Views
2K
  • Calculus and Beyond Homework Help
Replies
6
Views
2K
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
13
Views
803
Replies
5
Views
11K
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
852
  • Math Proof Training and Practice
Replies
25
Views
2K
Back
Top