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I need help badly

  1. Nov 30, 2006 #1
    I need help badly!!

    1. A bicycle rider pushes a bicycle that has a mass of 13 kg up a steep hill. The incline is 25* and the road is 275 m long. The rider pushes the bike parallel to the road with a force of 25N. How much work is done by the force of gravity on the bike?

    2. Your car has stalled and you need to push it. Suppose for the first 15 m, your force decreased at a constant rate from 210-40.0N. How much work did oyu do on the car? Draw a force-displacement graph to represent the work done during this period.

    Please help me. i am in need!!!!!
  2. jcsd
  3. Nov 30, 2006 #2


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    You need to know the definition of work. Can you state what it is as you understand it?
  4. Dec 1, 2006 #3
    In these two questions, mainly the first i don't understand which formula to used. the ones that i have are W = Fd and W = fdcos* <-- theta..
    and in the second question, i don't understand which formula to use either.
    Thank you for your help
  5. Dec 1, 2006 #4


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    For the first one, which component of gravity does work along the path?

    As for the second one, do you have any idea how you could calculate the work from the force-displacement diagram?
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