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: Building a weighing machine

  1. Jan 12, 2013 #1
    Project: Weighing machine based on potentiometer
    Principle: On changing the length of the wire current in the circuit will change which will change the deflection in the ammeter

    Set up: On top of four or three spring(same spring constant) a board is attached so when a weight is kept on top of it, the spring will compress and Jockey/slider attached with the board will slide on the wire and length changes

    Problem: the problem is that when a weight is kept on top of the board, the spring tries to bend and the distribution of the force is not uniform. So is there a way out so that the force of the springs will be uniformly distributed and the spring will not bend?
  2. jcsd
  3. Jan 12, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    A linear-coil spring is usually more laterally stable on expansion rather than compression.
    Replace board with basket - suspend basket from spring - put weights to be measured in basket.
    There are many designs that do what you want with your equipment - eg. look at how a 2-pan Roverbal balance works (with those it does not matter where the weights are placed in the pan: how do they do that?)
    Last edited: Jan 12, 2013
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook