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Homework Help: Finding total force - Is this correct?

  1. Sep 29, 2011 #1
    1. The problem statement, all variables and given/known data

    A weight lifter who has a mass of 90kg lifts a weight of 50kg, which accelerates the weight at a rate of 0.47 m/s^2

    Would the total force simply be (140kg)*(0.47m/s^2) = 65.8 n?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Sep 29, 2011 #2


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    That would actually be your net force. You forgot the force of gravity.

    Additionally, I don't think the weightlifter is accelerating into the air - only the weight.
  4. Sep 29, 2011 #3
    ahh, net force.

    Can you possibly point me in the right direction for total force for my example?
  5. Sep 29, 2011 #4
    Can anyone else help me out with this one?

    Thanks :)
  6. Sep 29, 2011 #5


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    You have the force of gravity on the weightlifter.

    You not only have the force of gravity on the weight, but the weightlifter is applying a force to accelerate it.

    This would be the total force applied to the floor the weightlifter is standing on.
  7. Sep 29, 2011 #6
    Thank you... How would I calculate this?

    So, I am asking to identify which laws are being used.

    This would be Newtons 3rd correct?
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