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By how much does your force change the kinetic energy

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  1. Nov 15, 2016 #1
    1. The problem statement, all variables and given/known data
    You push a blob of gelatin with a constant force of 2.4 F across a wet table on which it slides easily. Because the blob shape distorts, its center of mass moves only 33 mm during the time interval in which the point of application of your force moves 53 mm .
    By how much does your force change the kinetic energy of the center of mass?
    What is the work done by you on the blob?= 0.127 J

    2. Relevant equations
    w=ΔK
    ΔK=1/2mv^2

    3. The attempt at a solution
    w= 0.127 J
     
  2. jcsd
  3. Nov 15, 2016 #2

    Simon Bridge

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    Is there a question here?
    Does the sheer modulus have anything to do with this?
    Can you describe where the work-energy goes?
     
  4. Nov 15, 2016 #3
    By how much does your force change the kinetic energy of the center of mass?
    this is the question
     
  5. Nov 15, 2016 #4

    Simon Bridge

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    That was their question, not yours.
    That is the problem you have to solve - you just posted a bunch of stuff and left it to us to guess what you wanted. What was your question? Not theirs, yours.
    Please answer my other questions.
     
  6. Nov 15, 2016 #5
    my question is that i am lost and frusterated with this question and that i need help walking through it to figure out the answer
     
  7. Nov 15, 2016 #6

    Simon Bridge

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    Great! It is best not to make people guess what you want - and phrasing questions is an important part of the scientific method which you are learning.
    Can you answer the other two questions in post #2?
     
  8. Nov 15, 2016 #7
    i've never learned sheer modulus so i don't know. isn't the work going into the geletin
     
  9. Nov 16, 2016 #8

    I like Serena

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    Work = force times distance of mass center.
    The work is equal to the change in kinetic energy (unless the object starts to rotate or something like that).
     
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