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Homework Help: Finding distance from force

  1. Jan 22, 2010 #1
    1. The problem statement, all variables and given/known data
    A dockworker applies a constant horizontal force of 72.0N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 10.0m in a time 4.50s. If the worker stops pushing at the end of 4.50 , how far does the block move in the next 5.70s?


    2. Relevant equations
    v = at
    x = x0 + v0t + 1/2at^2


    3. The attempt at a solution
    I realized this is only a kinematics problem, but I keep getting the wrong answer. I got 32.1m, but the answer is 25.3m. I did v=at, plugging in 0.987654321*5.70 then multiplied this answer by 5.70. What am I doing wrong??
     
  2. jcsd
  3. Jan 22, 2010 #2

    ideasrule

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    Nothing. Unless you made a mistake in typing the question out, your answer is correct.
     
  4. Jan 22, 2010 #3
    Weird. I copied & pasted the exact question from the website. Stupid MasteringPhysics -____-
     
  5. Jan 22, 2010 #4

    rl.bhat

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    I did v=at, plugging in 0.987654321*5.70
    You have to find the velocity at the end of 4.5s.
     
  6. Jan 22, 2010 #5

    ideasrule

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    Oops, I somehow missed that too. Sorry magnifik!
     
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