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: What force does the dynamometer display?

  1. May 28, 2005 #1
    Hi! Really simple question:

    Two people are pulling on the ends of a dynamometer, each with a force of 25N. What force does the dynamometer display?

    Textbook answer: 25N

    I'm having a difficult time understanding this conceptually. Could anybody explain why the answer is 25N?

  2. jcsd
  3. May 28, 2005 #2
    If the other person wasn't pulling back, the dynomometer, would simply move towards the one person pulling it. It would therefore record zero.
    Having another person pulling back, is exactly the same as having one end secured to a wall/floor. Perhaps you can understand that idea better.

    This is a question about understanding Newton's third Law of Motion. Do you know that?
  4. May 28, 2005 #3
    Yes, it's clear now. Thanks!!!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook