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!

Pulleys and Spring Scales

  1. Mar 6, 2013 #1
    1. The problem statement, all variables and given/known data
    The question shows two 5kg masses at rest hanging from two pulleys on opposite ends of a table. The string is massless and the pulley is frictionless.


    2. Relevant equations
    They want to know what the spring scale reads (in the middle of the masslessstring).

    3. The attempt at a solution
    This is what I thought:

    Fspring= w=mg
    5kg*9.8m/s^2= 49N
    This answer was wrong.

    Would the answer be 98N since both masses are the same?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 6, 2013 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Assuming I understand the setup, the spring scale will read the tension in the string.

    I'd say that answer was correct. Why do you think it's wrong?

    No.
     
  4. Mar 6, 2013 #3
  5. Mar 6, 2013 #4

    Doc Al

    User Avatar

    Staff: Mentor

  6. Mar 6, 2013 #5
    I must be going crazy . What about the mass of the system? Wouldn't it be 10?
     
    Last edited: Mar 6, 2013
  7. Mar 6, 2013 #6

    Doc Al

    User Avatar

    Staff: Mentor

    If by "system" you mean both 5 kg masses together, then sure.

    What are the exact questions you are being asked?
     
  8. Mar 6, 2013 #7
    The string is massless and the pulley is frictionless. The spring sclae reads in kg. What is the reading of the scale?
     
  9. Mar 6, 2013 #8

    Doc Al

    User Avatar

    Staff: Mentor

    There's the problem: They want the answer in kg, not Newtons.
     
  10. Mar 6, 2013 #9
    So wouldn't the answer just be five because 49N is 5kg.
     
  11. Mar 6, 2013 #10

    Doc Al

    User Avatar

    Staff: Mentor

    Yes, the answer will be 5 kg.
     
  12. Mar 6, 2013 #11
    Thank you Doc Al. I highly appreciate it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Pulleys and Spring Scales
  1. Spring & pulley (Replies: 12)

  2. Spring scale (Replies: 8)

  3. Pulley on a Spring (Replies: 6)

  4. Pulleys and springs (Replies: 22)

Loading...