Taller de Hidrostática

Transcripción

1 Taller de Hidrostática MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Is the mass of iron greater than, less than, or equal to the mass of aluminum? 1) A) This is an incorrectly stated question. Iron and aluminum are types of material, mass is the property of an object. B) The mass of iron is equal to the mass of aluminum. C) The answer depends on temperature. D) The mass of iron is less than the mass of aluminum. E) The mass of iron is greater than the mass of aluminum. 2) Una esfera sólida de 6.1 kg hecha de metal cuya densidad es de 2500 kg/m3, cuelga de una cuerda. Cuando la esfera se sumerge en un líquido de densidad desconocida, la tensión en la cuerda es de 26 N. La densidad del líquido corresponde a: A) 1200 kg/m3 B) 1500 kg/m3 C) 1400 kg/m3 D) 1100 kg/m3 E) 1300 kg/m3 2) 3) Substance A has a density of 3 g/cm3 and substance B has a density of 4 g/cm3. In order to obtain equal masses of these two substances, the ratio of the volume of A to the volume of B will be equal to A) 4 : 3 B) 3 : 4 C) 2 : 1 D) 1 : 4 E) 1 : 3 3) 4) A styrofoam sphere of radius R has a density. You now carefully compress the sphere so its radius is R/2. What is the density of the compressed sphere? A) 4 B) 8 C) 8 D) 2 E) 2 4) 5) A solid right circular cylinder of a substance has a radius 10.0 cm and a height 12.0 cm. The mass of the cylinder is 4.00 kg. What is the density of the substance? A) kg/m3 B) kg/m3 C) kg/m3 D) kg/m3 E) kg/m3 5) 6) What is the mass of a solid sphere that has a density kg/m3 and a radius 10.0 cm? 6) A) 4.56 kg B) 15.0 kg C) 298 kg D) 62.8 kg E) kg

2 7) How a ship floats is described in terms of 7) A) Torricelli's equation. B) Bernoulli's principle. C) Pascal's principle. D) Poiseuille's equation. E) Archimedes' principle. 8) What is the radius of a sphere that has a density 5000 kg/m3 and a mass 6.00 kg? 8) A) 4.98 cm B) 1.27 m C) 7.22 cm D) 1.56 m E) 6.59 cm 9) A board that is 20.0 cm wide, 5.00 cm thick, and 3.00 m long has a density 400 kg/m3. The board is floating partially submerged in water. What minimum mass would need to be set on the board to completely submerge the board? A) 30.0 kg B) 18.0 kg C) 42.0 kg D) 12.0 kg E) 48.0 kg 9) 10) A spar buoy consists of a circular cylinder, which floats with its axis oriented vertically. One such buoy has a radius of 1.00 m, a height of 2.00 m and weighs 40.0 kn. What portion of it is submerged when it is floating in fresh water? A) 1.30 m B) 1.35 m C) 1.25 m D) 1.50 m E) 1.20 m 10) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 11) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always keeping the top and bottom faces horizontal. Which one of the following graphs best describes the absolute (total) pressure p on the bottom of this block as a function of time t if the block just enters the water at time t = 0 s? 11)

3 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 12) Que fuerza ejerce el agua (además de la que se debe a la presión atmósferica) sobre la ventana de un submarino de 46 cms de radio a una profundidad de 2300 metros en agua de mar (densidad 1025 kg/m3)? A) N B) N C) N D) N E) N 12) 13) What is the difference between the pressures inside and outside a tire called? 13) A) gauge pressure B) fluid pressure C) atmospheric pressure D) absolute pressure E) N/m2 14) At a certain depth in the ocean, the absolute pressure is p. If you go to twice that depth (treating the water as incompressible) A) the absolute pressure will be less than 2p. B) the absolute pressure will be greater than 2p. C) the gauge pressure will increase but will not double. D) the absolute pressure will be 2p. E) the gauge pressure will not change. 14) 15) When atmospheric pressure increases, what happens to the absolute pressure at the bottom of a pool? A) It increases by a lesser amount. B) It depends on the depth of the pool. C) It increases by a greater amount. D) It does not change. E) It increases by the same amount. 15) 16) The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the water pressure at that point? The density of seawater is 1025 kg/m3. A) Pa B) Pa C) Pa D) Pa E) Pa 16)

4 17) Si usted ha tenido que caminar por el agua a través de un riachuelo rocoso yendo de excursión en las montañas, probablemente se percató que en el momento en que usted llega al agua profunda en el centro del riachuelo las rocas no parecen lastimar tanto a sus pies desnudos Cuál és la razón de esto? A) Uno experimenta una mayor fuerza de flotación en agua profunda. B) La velocidad del agua es menor en regiones profundas que en regiones poco profundas. C) Uno tiende a pararse de puntillas en lo profundo, de tal modo que se reduce el área del pie que hace contacto con las rocas. D) El agua profunda es más fría, y por lo tanto más densa, que el agua superficial. E) Le mayor presión a los pies de uno en agua profunda provoca que las rocas no lastimen tanto. 17) Figure ) Un contenedor tiene un tubo vertical, cuyo radio interno es de mm, conectado a él por un lado. Un líquido desconocido alcanza el nivel A en el contenedor y el nivel B en el tubo, el nivel A está 5.0 cm encima del nivel B. El líquido soporta una columna de aceite de 20.0 cm de alto, entre los niveles B y C, cuya densidad es de 680 kg/m 3. En la Figura 14.1, la presión manométrica corresponde a: A) 670 Pa B) 1300 Pa C) 1700 Pa D) 2000 Pa E) 1000 Pa 18) FIGURE ) A reservoir manometer consists of a U-tube in which the two arms have different diameters, as shown in Fig The diameter on the narrow side is 10.0 mm and the diameter on the reservoir side is 25.0 mm. The liquid in the manometer is oil with a density of 830 kg/m3 and the fluids in contact with the oil are gases of negligible density. The dotted line indicates the level of the oil when the pressures p 1 and p 2 are equal. What is the value of h when P 1 - P 2 = 1000 Pa? A) 13.2 cm B) 12.3 cm C) 10.6 cm D) 8.40 cm E) 9.81 cm 19)

5 FIGURE ) The two water reservoirs shown in Fig are open to the atmosphere. The manometer contains mercury with a density of 13,600 kg/m3. What is the difference in elevation h if the manometer reading m is 25.0 cm? A) 4.20 m B) 1.58 m C) 3.75 m D) 3.15 m E) 3.40 m 20)