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Conservation of forces and poetential energy

  • Thread starter MEAHH
  • Start date
  • #1
10
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conservation of forces and poetential energy!!!

Homework Statement


a potential energy function for a 2d force is of the form U=3x^3y-7x. find the force that acts at the piont (x,y).


Homework Equations



U=3x^3y-7x

The Attempt at a Solution



how do i do this? tahe the derivative?
 

Answers and Replies

  • #2
454
0

Homework Statement


a potential energy function for a 2d force is of the form U=3x^3y-7x. find the force that acts at the piont (x,y).


Homework Equations



U=3x^3y-7x

The Attempt at a Solution



how do i do this? tahe the derivative?
Yes. You might want to reread what your textbook says about the gradient of the potential energy function.
 
  • #3
10
0
ok so i took the derivatives with respect to x and y
d/dx=9x^2y-7 and d/dy=3x^3
what do i do now? Subtract then, this chapter in my book dosen't talk about the gradient.
 
  • #4
454
0
The gradient is the vector idU/dx + jdU/dy (in two dimensions)
see also http://en.wikipedia.org/wiki/Gradient" [Broken]
 
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