Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B What will be the weight measured by the balance?

  1. Sep 12, 2016 #1
    Suppose there is a beaker filled with water placed on a weighing machine. Suppose the reading is x kg. Now, if i immerse a solid block inside the beaker without touching the walls or the bottom of the beaker, will the reading given by the weighing machine increase or not?
     
  2. jcsd
  3. Sep 12, 2016 #2

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Depends ... give us the complete statement of the problem.
     
  4. Sep 12, 2016 #3
    Actually the problem was like this:
    A beaker containing water is suspended from a spring balance. Does the reading of the spring balance change
    (a)When a piece of stone suspended from a string is immersed in water without touching the beaker?
    (b)When a piece of iron or cork is put in water in the bucket?
     
  5. Sep 12, 2016 #4
    Initially you have mass of x Kg which represents beaker filled with some water....now you are having beaker +water +mass(immerged) so mass has changed therefore it should show some increase in the weight of the new system on the pan....but i wish to know from you the reason behind raising this question....
    my guess is that you may be thinking that the liquid/water is supporting the mass so that how it will effect the weight.....then you may imagine yourself standing on the weighing machine and then drink a litre of juice ....should the weight increase or not?
     
  6. Sep 12, 2016 #5
    @drvrm I asked this question because intuitively it seems to me that there should not be any rise in the reading of the balance since the object does not touch the walls of the beaker.
     
  7. Sep 12, 2016 #6

    Dale

    Staff: Mentor

  8. Sep 12, 2016 #7
  9. Sep 12, 2016 #8

    Dale

    Staff: Mentor

    Draw a free body diagram of the stone before and after immersion. What do you notice?
     
  10. Sep 12, 2016 #9
    Before immersion the force acting on the body is the force of gravity and the force exerted by us to balance the force of gravity and after immersion the force acting on the stone is the force of gravity, the force exerted by us to balance the force of gravity and the buoyant force exerted by the water.
     
  11. Sep 12, 2016 #10

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Does it overflow?
    You've still got "no change/increase/decrease" possibilities.
     
  12. Sep 12, 2016 #11
    It may or it may not. That is not mentioned.
     
  13. Sep 12, 2016 #12

    Dale

    Staff: Mentor

    Good, I think you have it from here.

    For future reference, please post homework questions in the appropriate forum:
    https://www.physicsforums.com/forums/introductory-physics-homework.153/
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What will be the weight measured by the balance?
  1. Coke in weight balance (Replies: 2)

  2. See saw weight balance (Replies: 6)

  3. How does a scale work? (Replies: 6)

Loading...