PHY11L - E206 ARCHIMEDES’ PRINCIPLE

 

EXPERIMENT 206:  ARCHIMEDES' PRINCIPLE

 

 

 

 

 

 

DATA and OBSERVATIONS

 

TABLE A. Determination of Specific Gravity of Unknown Solid Samples Heavier than Water
	Sample 1	Sample 2
weight in air,	48902        dynes	33.4                 dynes
weight in water,	43218         dynes	19600                 dynes
Specific Gravity,	8.60	2.74
Name of Sample (see table 1)	Brass	Aluminum

 

 

TABLE B. Determination of Specific Gravity of Unknown Liquids
	Sample 1	Sample 2
weight in air,	48902         dynes	48902         dynes
weight in water,	43218           dynes	43218           dynes
Weight in the liquid,	43414           dynes	43904          dynes
Loss of weight in liquid,	5488            dynes	4998            dynes
Specific Gravity,	0.966	0.879
Name of Sample (see table 1)	Water	Benzene

 

TABLE C. Determination of Specific Gravity of Unknown Liquids Using Hydrometer
	Sample 1	Sample 2
Specific Gravity	1.00	0.88
Name of Sample (see table 1)	Water	Benzene

 

 

EXPERIMENT 206:  ARCHIMEDES' PRINCIPLE

 

 DATA and OBSERVATIONS

 

TABLE D. Determination of Specific Gravity of Solid Lighter than Water
Name of sample : CORK
weight of cork in air,	2058                        dynes
weight of cork in air and sinker in water,	45276                       dynes
weight of both sinker and cork in water,	43120                        dynes
Specific Gravity,	0.955

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  PROBLEMS

 

 

1.         One kg of iron (S.G = 7.50) and one kg of brass (S.G = 8.44) are suspended from different balance scales, each metal fully submerged in water. What is the weight loss for each metal?

 

S.G.  = Weight in air         Weight loss = weight in air

                Weight loss                                              S.G.

 

 

            Weight loss (iron)  =   1000 g = 133.33 g

                                                          7.5        

 

Weight loss (brass)  =   1000 g = 118.48 g

                                                            8.44   

 

           

2.       A beach ball has a volume of 0.050 m³. How much force would you have to exert to hold this beach completely    

      underwater? Assume the weight of the ball is negligibly small.

 

F = VG

ρ = 1000k/m³

F = 1000(0.5)(9.8)

F = 490 N  

any force greater than 490 N, will submerge the ball.

 

3.       A sinker was used to submerge a piece of cork beneath the water to determine the cork's specific gravity. Why is it unnecessary to know the specific gravity of the sinker?

 

It is unnecessary to know the specific gravity of the sinker since the sinker is only used as a force that will submerge the cork. Only the weight (mass) of the sinker is needed because it is used in the formula for getting the specific gravity of the cork. From this formula, we can say that the SG of the sinker is not important.