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Problem with Energy Dissipation

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  1. Apr 30, 2017 #1
    1. The problem statement, all variables and given/known data

    A 4.70-kg steel ball is dropped from a height of 11.0 m into a box of sand and sinks 0.500 m into the sand before stopping. How much energy is dissipated through the interaction with the sand? Express answer using three significant digits.
    2. Relevant equations
    Potential Energy = mhg
    Mechanical Energy = (1/2)mv^2

    3. The attempt at a solution
    I thought that the energy dissipated would be equal to the potential energy at the start of the problem. So I found the initial potential energy with the equation mgh = (4.7)(11)(9.8) = 507 However, I submitted this answer and the program said it was incorrect.
     
  2. jcsd
  3. May 1, 2017 #2

    TSny

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    Hello. Welcome to PF!

    What is the total distance the ball travels vertically?
     
  4. May 1, 2017 #3
    I guess it falls 11.5 m including the distance in the sand. Do I include the distance in the sand?
     
  5. May 1, 2017 #4

    TSny

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    Is there any change in gravitational potential energy when the ball moves 0.5 m downward in the sand?
     
  6. May 1, 2017 #5
    Yeah there is. That makes a lot of sense. Thanks for your help!
     
  7. May 1, 2017 #6

    TSny

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    OK. Hope it works out now.
     
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