Tbr physics bouyancy chapter 7

crazy person

Full Member
5+ Year Member
May 7, 2011
90
3
  1. Pre-Medical
    example 7.4b page 63:

    why is the mg 36 N pointing down? shouldn't be pointing up because its says it weights in the air and 9 newtons should be ponting down because it specifically says 9 newtons in water? did they know it was already sunken before doing any calculation because of the specific gravity ratio?

    So do we always use the specific gravity ratio pobject/pwater for sunken objects only?

    I really don't like Fluids !
     

    caereax

    Full Member
    5+ Year Member
    Dec 18, 2011
    55
    0
      The picture is a free body diagram of all forces acting on the object.

      36N downward is the force of the object's weight.
      9N upward is the normal force (in water it weighs 9N, thus the ground pushes upward 9N).

      If an object still has weight in water that means it has sunk to the bottom. As for the ratio, you can use it whether an object is sunken or floating. If the object is sunken, the density ratio will represent the weight-to-buoyancy ratio. If the object is floating, the density ratio represents the % submerged.

      Also, if English is a second language, no problem on this post. If English is your first language, FFS, what are you doing?
       
      This thread is more than 8 years old.

      Your message may be considered spam for the following reasons:

      1. Your new thread title is very short, and likely is unhelpful.
      2. Your reply is very short and likely does not add anything to the thread.
      3. Your reply is very long and likely does not add anything to the thread.
      4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
      5. Your message is mostly quotes or spoilers.
      6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
      7. This thread is locked.