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Integral form of momentum equation

  1. Jun 25, 2016 #1
    Hello guys!
    can i get the derivation for this equation ?

  2. jcsd
  3. Jun 25, 2016 #2
    I think the first term should be a partial derivative with respect to time t (not x), and represents the rate of accumulation of x-momentum within the control volume. The second term represents the net rate of x-momentum leaving the control volume.
  4. Jun 25, 2016 #3
    yes sir as you said the 1st term should be the partial derivative with respect to time but i don't know why our teacher in the fluid class wrote the equation in this form, and it was not a mistake because he used it again and again, can you explain the logic behind it as he is a very senior teacher and he wouldn't make such a silly mistake
  5. Jun 25, 2016 #4
    I stand by what I said. I can't account for what your teacher does. All I can do is confidence in what I am saying.

    My questions for you are:

    1. How does his equation account for the time rate of accumulation of x momentum within the control volume?

    2. When he writes the corresponding equation for the conservation of mass within the control volume, does his equation have a partial derivative with respect to x or a partial derivative with respect to t?
  6. Jun 25, 2016 #5
    Here's a couple of more questions for you:

    1. What are the units of the term as your teacher has written it?

    2. Are those units of force?
  7. Jun 27, 2016 #6
    So.... What are your answers to my questions?
  8. Jun 28, 2016 #7
    sorry i asked him and he said its partial by partial t and not x his writing style is different so i mistakenly wrote it as partial by partial x
  9. Jun 28, 2016 #8
    No problem.
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