Fluid Mechanics - find a cavity of a block if it exist?

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SUMMARY

The discussion centers on calculating the size of a cavity within a submerged 10cm aluminum cube, given its density of 2700 kg/m³ and a measured weight of 13N in water. The buoyancy is calculated using the formula B = V * P_water * g, where V is the volume of the cube, P_water is the density of water, and g is the acceleration due to gravity. The attempt to find the volume of the cavity involves the equation V_0 = V - V_c, leading to confusion when the calculated values yield unexpectedly small results. The participants emphasize the importance of comparing the measured weight in water with the predicted weight to determine the presence of a cavity.

PREREQUISITES
  • Understanding of buoyancy principles and Archimedes' principle
  • Familiarity with basic physics equations involving density and volume
  • Knowledge of unit conversions, particularly between metric units
  • Ability to perform calculations involving forces and weights in fluid mechanics
NEXT STEPS
  • Study the principles of Archimedes' principle in fluid mechanics
  • Learn how to calculate buoyancy for irregular shapes
  • Explore the concept of density and its applications in material science
  • Investigate the effects of submerged objects on fluid displacement
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This discussion is beneficial for students studying fluid mechanics, physics enthusiasts, and engineers involved in material analysis and buoyancy calculations.

mistax
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Homework Statement



You are given a 10cm Cube of aluminum with Density of 2700kg/m is submerged in water and the weight in water is 13N. If a cavity exist how big is it?

Homework Equations



The equation i used were B = V * P_water * g to find buoyancy.

To find the enclosed cavities i used V_0 = V - V_c = B/(p_water * g) - W/(p_m*g)

The Attempt at a Solution



for B i did volume of the cube was .1^3 * 1000KG/M for water * 9.8

and then when plugging into the equation for enclosed cavities i got
9.8/(9.8 * 1000kg/m) - 13N/(2700KGM * 9.8)

from there i got stuck since i got a number that was really small.
 
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I prefer to work through stage by stage.
Can you calculate the upthrust (buoyancy) produced by a 0.1m x 0.1m x 0.1 m in water?
I think you have calculated the weight of a cube of aluminium, assuming it has no cavity.
So can you check if there is any difference between the measured weight of the block in water and the predicted weight?
 

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