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: Man standing on a scale

  1. Jan 5, 2017 #1
    1. The problem statement, all variables and given/known data
    Man standing on scale and pulling on a rope connected to two pulleys

    2. Relevant equations
    The mass of the man is: m=100 kg

    The weight of the pulleys, cables, balance, and the frictions are not taken into account

    g=10m x s-2

    3. The attempt at a solution

    the force that the man should draw in order to maitain balance:
    T1=250 N

    The weight displayed on the scale:
    P= 125 kg

    Other tensions:
    T2=250 N
    T3=500 N
    T4=500 N
    T5=1000 N

    Do your agree with that ?
    Thank you..

    Attached Files:

    Last edited: Jan 5, 2017
  2. jcsd
  3. Jan 5, 2017 #2
    You have not laid out the question properly ... what information is given in the question?
  4. Jan 5, 2017 #3
    You just have to validate or not thes values (T1, P, T2, T3, T4, T5)
  5. Jan 5, 2017 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I agree with all the tensions, but I do not understand how you got 125kg for the scale reading. Consider again which way the forces act on the man.
  6. Jan 5, 2017 #5
    I'm not convinced either
    I thought about it..
  7. Jan 5, 2017 #6
    Yes I agree there is something wrong

    What do we know for sure ? ....T1= T2 and T3 =T4 ...... 4xT1 = 2xT4 = T5 and T5 is supporting all the mass = 100kg = 1000N ... so all the tensions are correct .

    The weight indicated on the scale must be the man's weight , minus the the pull from T1 .... 1000 - 250 = 750N scale should indicate 75Kg not 125kg
  8. Jan 5, 2017 #7
    Yes you are right :check:

    Thank you.. it's cool :oldbiggrin:
  9. Jan 5, 2017 #8


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    This is a homework forum. We point out errors, provide hints, explain principles.... We do not post solutions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted