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Mass, force, speed?

  1. Jan 3, 2005 #1
    i have this question

    a crane is raising a steel beam (350 kg) the max tension the supporting cable can take without breaking is 7000 Newtons

    a) is it safe to life the beam at a constant speed of 3m/s? prove answer

    (the only idea i have is the use of f=ma, but then i am stuck w/acceleration when i need to use speed i just don't know what to do.)
    :confused: :confused: :confused:
    Last edited: Jan 3, 2005
  2. jcsd
  3. Jan 3, 2005 #2
    if something is travelling at a constant speed, what is its acceleration? What does this mean about your NET force?
  4. Jan 3, 2005 #3
    As a physics student, I cannot be completely sure of answering this as some of experts in this forum would, but I'll do it anyway..

    Don't be too mindful of the "3m/s" as a quantity.
    however, be mindful that it's moving at a constant speed.
    That means there is NO acceleration.

    As Dave said, what does that make your Net force?

    Draw a free body diagram to see what forces are acting on the steel beam.
    Then see if the tension on the cable is greater than 7,000 Newtons.
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