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What is the weight of a 19kg stone?

  1. Jan 21, 2007 #1
    1. The problem statement, all variables and given/known data
    a)What is the weight of a 19kg stone?
    b)what force if required to raise the stone without acceleration.

    2. Relevant equations
    weight=mg
    Fnet=ma

    3. The attempt at a solution
    A)9.8N/kg*19kg
    =186kg
    B)didnt get how to this part
     
  2. jcsd
  3. Jan 21, 2007 #2

    Kurdt

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    Part a) is correct apart from the units.

    Part b) what do you know of Newton's laws? I think you have to neglect the initial acceleration and consider the stone being raised at a constant speed.
     
  4. Jan 21, 2007 #3
    is the answer to Part B gravity
     
  5. Jan 21, 2007 #4

    Kurdt

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    Whats Newton's first law?
     
  6. Jan 21, 2007 #5
    is it inertia
     
  7. Jan 21, 2007 #6

    Kurdt

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    Newton's first law states that an object will remain stationary or at uniform velocity if no net force acts upon it.
     
  8. Jan 21, 2007 #7
    so for part B the answer is that the net force must raise it
     
  9. Jan 21, 2007 #8

    Kurdt

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    Yes in a manner. But its a little more complicated.
     
  10. Jan 21, 2007 #9
    do i have to do any calculations for the anser
     
  11. Jan 21, 2007 #10
    Not to be picky:biggrin: but grams and kilograms are not a measurment of weight, they are a measurment of mass. Also newtons second law is F=ma. 19kilograms is right but if i'm correct you should have 9.8m/s not N/kg. Lastly:biggrin: 9.8m/s*19kg would equal 186 newtons, or just about 41 pounds.

    hope i helped
     
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