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!

Net external work

  1. May 7, 2013 #1
    Quick question about net external work

    Got a block (A) attach to Spring which attach to a Wall
    Hand pushes A toward the wall which compress the Spring

    So hand is doing positive work on A, W = F*D, work is whatever force by hand times distance..
    But work done ON the spring BY the wall is zero right? wall didn't move, spring didn't move?

    if zero for the wall, then the net external work on the system (block A + Spring) is just the work done by hand, the same W = F*D ?
  2. jcsd
  3. May 7, 2013 #2


    User Avatar

    Staff: Mentor

    Hi kykk. [Broken]

    That sounds right.

    Yes. If the wall hadn't pushed back, the hand would have had nothing to push against and could not have done any work here.
    Last edited by a moderator: May 6, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook