Mapua Institute of TechnologyDepartment of Physics

Experiment 206ARCHIMEDES PRINCIPLE

Name: Salazar, Abigail B.

GRADEProgram/Year: CE-2Course Code/ Section: PHY11L/A1Student No.: 2012101116Group no.: 03 Seat No.: 15Date of Performance: November 24, 2014Date of Submission: December 1, 2014

Ramil R. JimenezInstructor

DATA and OBSERVATIONSTABLE A. Determination of Specific Gravity of Unknown Solid Samples Heavier than Water

Sample 1Sample 2

Weight in air, 33.4 g49.8 g

Weight in water, 21.1 g44.0 g

Specific Gravity, 2.78.6

Name of SampleAluminumBrass

Percent Error0.57 %1.72 %

TABLE B. Determination of Specific Gravity of Unknown Liquids

Sample 1Sample 2

Weight in air, 33.4 g33.4 g

Weight in water, 21.1 g21.1 g

Weight in the Liquid,

23.2 g21.3 g

Loss of weight in Liquid,

10.2 g12.1 g

Specific Gravity, 0.829260.98373

Name of SampleAlcoholWater

Percent Error1.123 %1.640 %

TABLE C. Determination of Specific Gravity of Unknown Liquids Using Hydrometer

Sample 1Sample 2

Specific Gravity, 0.821.00

Name of SampleAlcoholWater

Percent Error0.00 %0.00 %

TABLE D. Determination of Specific Gravity of Solid Lighter than Water

Name of Sample: CORK

Weight of cork in air, 1.7 g

Weight of cork in air and sinker in water,

22.9 g

Weight of both cork in air and sinker in water,

16.6 g

Specific Gravity, 0.269841

SAMPLE COMPUTATIONTABLE A. Determination of Specific Gravity of Unknown Solid Samples Heavier than WaterSample 1Weight in air, = 33.4 gWeight in water, = 21.1 g

Specific Gravity = =

Name of Sample: AluminumPercent Error

Sample 2Weight in air, = 49.8 gWeight in water, = 44.0 g

Specific Gravity = =

Name of Sample: Brass

Percent Error

TABLE B. Determination of Specific Gravity of Unknown LiquidsSample 1Weight in air, = 33.4 gWeight in water, = 21.1 gWeight in the Liquid, = 23.2 g

Loss of weight in liquid,

Specific Gravity = =

Name of Sample: AlcoholPercent Error

Sample 2Weight in air, = 33.4 gWeight in water, = 21.1 gWeight in the Liquid, = 21.3 g

Loss of weight in liquid,

Specific Gravity = =

Name of Sample: WaterPercent Error

TABLE C. Determination of Specific Gravity of Unknown Liquids Using Hydrometer

Sample 1Specific Gravity = 0.82Name of Sample: AlcoholPercent Error

Sample 1Specific Gravity = 1.00Name of Sample: WaterPercent Error

TABLE D. Determination of Specific Gravity of Solid Lighter than Water

Name of Sample: CORKWeight of cork in air,

Weight of cork in air and sinker in water,

Weight of both cork in air and sinker in water

Specific Gravity,

ANALYSIS1. When a body is submerged in a liquid, what factor determines the amount of buoyant force on it?

When a weight is added in pan1, the position of pan1must be closer to the axis of rotation than its original equilibrium position. Pan2which has no additional weight must be farther than the distance of the lever arm of Pan1and vice-versa when weight is added on pan2.

2. If a body floats in water, how does the buoyant force acting on it compare with its weight?

In Part B of the experiment, the angle of the spring balance affects the equilibrium because the spring balance does not give an accurate reading when it is not hanged upright. What happened is that when it has an angle, the equilibrium can still be achieved but the resulting force measured will not be accurate.

3. Does wetting the cork first before getting its weight in air affect the result of the experiment? Defend your answer

In getting the weight of the beam, the support of the beam must be transferred to the second holeas the axis of rotation so that the center of gravity of the beam does not pass through the new axis of rotation. Equating the torque of the center of gravity of the beam and the torque of the pan and the added weight by letting the weight of the beam as the unknown will lead to the formula:

CONCLUSION:1. What is the relationship between a bodys weight in air and the buoyant force on it when it is submerged in water?

Though for a given body mass is constant, moment of inertia is not, because of the external forces that act on the system. These external forces are the place of the axis of rotation, how far the mass units are from that axis and also the distribution of weight so even if the mass is constant, and the moment of inertia changes significantly due to these forces. Moment of inertia depends on many factors and the change of these factors will cause the change in moment of inertia.

2. What factors determine the buoyant force on a body submerged in a liquid?

There are many factors that affect the moment of inertia of a rigid body. The moment of inertia depends on its mass distribution; the further away a mass point, the larger its contribution to the moment of inertia. It also depends on a relative position of particles from the axis of rotation and the position of axis of rotation

3. A ship floats while a coin sinks in water. ExplainAn object remains in a state of uniform rotational motion unless acted on by a nettorque. Further, the angular acceleration of an object is proportional to the net torque acting on it, which is the analog of Newton's Second Law of motion. A net torque acting on an object causes a change in its rotational energy. Moment of inertia is related to angular acceleration from the formula of torque:torque = moment of inertia x angular acceleration

RESEARCH/APPLICATIONS:

1. Samuel Dixon uses the moment of inertia of the long rod to help maintain balance as he crosses the Niagara river (1890).

2. Aflywheelis a wheel with a large moment of inertia used to smooth out motion in machines. This example is in a Russian museum.

3. Figure skaters can reduce their moment of inertia by pulling in their arms, allowing them to spin faster due to conservation of angular momentum

en.wikipedia.org/wiki/Moment_of_inertiahttp://www.real-world-physics-problems.com/rotational-inertia.html