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Work phythagorean theorem Question

  1. Oct 23, 2005 #1
    this is drivnig me nuts ive doen eveyrthin gon the worksheet but this is a wierd one

    A unifrom rectangular marble slab is 3.4m long and 2.0m wide. It has a mass of 180KG. If it is originally lying on the flag ground, how much work is needed to stand it on end.

    I know work = force X distance
    and to get force i multiply 180X9.8 like ive doen in all the other questions
    but whats teh distance here it rises, it ried phythagorean theorem to get the distance and all these wierd aways
    but the asnwer should be
    3000 J
    dont nkow what to do!
  2. jcsd
  3. Oct 23, 2005 #2
    and another
    Q1 was)
    A 200 kg cart is pushed slowly up an incline. How much work does the pushing force do in moivng the cart up to a platorm 1.5m above the starting point if frciton is negligible

    that was fairly easy, (200X9.8) = 1960 X 1.5 = 2940 J

    Q2 is )
    Repeat Q1 if the distance along hte incilne to the platofrom is 7m and a fricotin force of 150N opposes the motion.
    I didnt know how to handle this, but i see doing 7X150 = 1050
    and adding that to the first asnwer 2940J gives me the right answer
    can anyone expalin why this worked?
    i thoguht id have to do 1960X7 instead and what would i do with force
  4. Oct 23, 2005 #3
    please ppl!
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