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Volume help

  • Thread starter badman
  • Start date
  • #1
57
0
im having a really hard time trying to figure this out.
An ore sample weighs 19.8 N in air. When the sample is suspended by a light cord and totally immersed in water, the tension in the cord is 11.5 N.

Find the total volume of the sample.
Take the density of water to be rho_water = 1000 kg/m^3 and the free fall acceleration to be g = 9.80 m/s^2.


heres the equation i figured out for this type of problem.

force of buoyancy=density*volume* gravity.

alright is the force of buoyancy for air and water 19.8 and 11.5 respectively?
if so wont i just have to multiply grvity times thhier densities divided by the force to find the volumes then add them up?
 

Answers and Replies

  • #2
Fermat
Homework Helper
872
1
You can neglect the buoyancy for air - it's neglible.
The difference in tension in the cord is 19.8 - 11.5 = 8.3 N.
The displacement of the water by the mass has provided this buoyancy force (8.3N)

now use the eqn you worked out.
 

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