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Unformatted text preview: 1 Density Density is defined as mass per unit volume. Specific Gravity (SG) = Density / Density of water at 4 o C Fluids 2 The density in kilograms per cubic meter can be obtained by multiplying the table values by 1000. Solids Magnesium 1.7 Aluminum 2.7 Copper 8.39.0 Gold 19.3 Iron 7.8 Lead 11.3 Platinum 21.4 Uranium 18.7 Osmium 22.5 Ice at 0 C 0.92 Gases at STP Air 0.001293 Carbon dioxide .001977 Carbon monoxide 0.00125 Hydrogen 0.00009 Helium 0.000178 Nitrogen 0.001251 Material Density (gm/cm 3 ) Liquids Water at 4 C 1.0000 Water at 20 C 0.998 Gasoline 0.70 Mercury 13.6 Milk 1.03 2 The density in kilograms per cubic meter can be obtained by multiplying the table values by 1000. Solids Magnesium 1.7 Aluminum 2.7 Copper 8.39.0 Gold 19.3 Iron 7.8 Lead 11.3 Platinum 21.4 Uranium 18.7 Osmium 22.5 Ice at 0 C 0.92 Gases at STP Air 0.001293 Carbon dioxide .001977 Carbon monoxide 0.00125 Hydrogen 0.00009 Helium 0.000178 Nitrogen 0.001251 Material Density (gm/cm 3 ) Liquids Water at 4 C 1.0000 Water at 20 C 0.998 Gasoline 0.70 Mercury 13.6 Milk 1.03 3 Pressure 4 Pressure 5 Pressure Equation The pressure on a surface is the perpendicular force per unit area acting on the surface. Pressure is force per unit area: units: Newton/(meter) 2 =Pascal (Pa) pressure exerted by the weight of a dollar bill is about 1 Pa 1 atmosphere is about 1.103 5 Pa direction: always perpendicular to surface 6 At Sea level: 1 atm = 101325 Pa 1.013 10 5 Pa = 760 mmHg = 760 Torr At some heights above the earth are: Height Measured Predicted pressure pressure 30 km (19 mi) 9.5 torr 25 torr 60 km (37 mi) 0.21 torr .8 torr 90 km (56 mi) 0.0019 torr .03 torr Atmospheric Pressure (atm ) 7 Example: Pressure is force per unit area. A force of 150 N applied to a piston of area 0.001 m 2 in a tire pump results in a pressure of 1.5 x 10 5 N/m2 = 1.5 x 10 5 Pa. 8 Example: What is the pressure on the base of the bathtub? The volume of water is = (length) (width) (height) = l*h*w =0.234 m 3 The weight = volume *density * gravity = 2293.2 N Force (F) = weight = 2293.2 N Pressure (P) = weight / area = 2940 N/m 2 9 Examples 1. The contraction of the left ventricle (chamber) of the heart pumps blood to the body. Assuming that the inner surface of the left ventricle has an area of 79 cm 2 and the maximum pressure in the blood is 125 mmHg, estimate the force exerted by the ventricle at maximum pressure. 10 Right Heart receives blood from the body and pumps it through the pulmonary artery to the lungs where it picks up oxygen....
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This note was uploaded on 01/02/2012 for the course PHYS 1149 taught by Professor Bala during the Fall '11 term at Northeastern.
 Fall '11
 Bala
 Gravity, Mass

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