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!

Calculation of work

  1. Nov 18, 2007 #1
    1. The problem statement, all variables and given/known data

    The (non-conservative) force propelling a 1.10 x 10(3)-kg car up a mountain road does 6.80 x 10(6) J of work on the car. The car starts from rest at sea level and has a speed of 22.0 m/s at an altitude of 1.90 x 10(2) m above sea level. Obtain the work done on the car by the combined forces of friction and air resistance, both of which are non-conservative forces.
    Calculate the work done by non-conservative forces using Wnc = dKE +DPE where
    Wnc= W friction+W air+W engine

    2. Relevant equations
    I used W1= .5MV2 + MGH
    required W =W1-W

    3. The attempt at a solution

    .5*1100kg*(22squared m/s) + 1100kg*9.8*192m = 2335960J

    2335960-6800000 = -1655960J
    What did I do wrong?
  2. jcsd
  3. Nov 18, 2007 #2


    User Avatar
    Homework Helper

    Work done on the car - work done by the car = loss of energy due to friction, air resistance.
  4. Nov 18, 2007 #3
    the 2335960-6800000 gives -4464040 which is the correct answer. Too tired to see how unreasonable the first result was!!!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Calculation of work
  1. Calculating Work (Replies: 2)

  2. Calculating work (Replies: 2)

  3. Calculating work (Replies: 0)

  4. Calculating work (Replies: 15)

  5. Calculating Work (Replies: 1)