1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bicycle coasting up a Hill

  1. Feb 19, 2007 #1
    1. The problem statement, all variables and given/known data

    Coasting along at 7.10 m/s, a 60.0 kg bicyclist on a 7.60 kg bicycle encounters a small hill. If the speed of the bicyclist is 6.00 m/s at the top of the hill, how much work was done on the bicyclist and her bike?


    2. Relevant equations

    KEf-KEi=W
    .5mvi^2-.5mvf^2
    kg*m^2*s^-2
    m=60kg+7.60kg
    v=m/s


    3. The attempt at a solution

    I tried finding the loss in KE and having that be the work done. I get

    .5mVf^2 -.5mVi^2
    .5*67.6kg*36 - .5*67.6kg*50.41

    I get -487 J and it tells me this is the wrong answer? What did I do wrong?
     
    Last edited: Feb 19, 2007
  2. jcsd
  3. Feb 19, 2007 #2

    berkeman

    User Avatar

    Staff: Mentor

    Please write out the whole equations. Include the mass and the units.
     
  4. Feb 19, 2007 #3
    Your final expression is incorrect mathematically.
     
  5. Feb 19, 2007 #4
    I relized i posted that wrong but the answer comes out to -487 the right way but thats the wrong answer. I edited and wrote everything out.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?