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!

Force and Work

  1. May 31, 2008 #1
    1. The problem statement, all variables and given/known data

    Our teacher made an unconvincing argument based on this example:
    If a horizontal force of 15 N were a applied to a 2 kg block, and the work done was 20 J, what distance did the object move?

    2. The attempt at a solution
    Using W=F*d the teacher solved this: 20 J=15 N*x -> x=4/3 m.
    This implied that if I applied 15 N to an object of any mass and did 20 J of work, the distance I could move the object is always the same. There seems to be something fundamentally wrong with this statement. But I'm not seeing what it is, I know it's there - I'm think that somehow I need to do something with the weight of the object. I mean if it were to be realistic I would have to calculate friction and gravity too...

    Can somebody please tell me what I missed out?
     
  2. jcsd
  3. May 31, 2008 #2
    That's correct.

    Usually we neglect friction and the gravity doesn't play a role here because this is a horizontal motion.
     
  4. May 31, 2008 #3
    it's more like a resultant force of 15N which moves the body 4/3 m when 20 J of work is done. the 15 N resultant force may include the force you apply - any resistive forces for example.
     
  5. May 31, 2008 #4
    Oh I see what you're saying, I guess my teacher didn't convey that point very well^^
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Force and Work
  1. Work and force (Replies: 1)

  2. Force and Work. (Replies: 2)

  3. Work and forces (Replies: 4)

  4. Work and forces (Replies: 9)

Loading...