1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Symbols in the equation relating work, force, and distance moved

  1. Oct 15, 2012 #1
    I have been taught that work = force x distance moved in direction of force, or


    However, should this not be W=Fs, as what is really meant is displacement (s), not distance (d)?

    Thank you - I sense that this is something the real Dr Moriarty would have known....
  2. jcsd
  3. Oct 15, 2012 #2
    If you move in a circular trajectory on your bicycle. Do you mean to say that the total energy you have spent is 0?

    I have been taught that A = Fs aswell, s is the distance travelled by the influence of the Force, so it would make no sense if the summarum is 0.
  4. Oct 15, 2012 #3
    My question is less about the actual physics, and more about the convention - it seems to me that writing W=Fd is inaccurate, as d represents distance, not displacement (s).
  5. Oct 15, 2012 #4


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Dr Moriarty! Welcome to PF! :smile:
    The correct equation is W = ∫ F · ds

    (since neither the force nor the direction of motion need be constant).

    W = Fd is just a simplification which applies in some circumstances. :wink:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook