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Physics Fluid Test
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Preguntas del test (42)
1In an experiment, a student releases an object from rest in four different liquids and observes whether it floats. The results are listed in the table. Which of the following is true about the density of the object?
- AIt is greater than the density of each of the liquids.
- BIt is the same as the density of distilled water.
- CIt is between the density of distilled water and the density of salt water.
- DIt is less than the density of each of the liquids.
2A student wants to determine whether the density of a solid cube of copper will decrease as its temperature is increased without melting the cube. Graphing which of the following will allow the student to study this question?
- ATemperature as a function of time
- BVolume as a function of temperature
- CMass as a function of time
- DMass as a function of temperature
3Students are investigating the change in the density of water as the temperature of the water increases. The students measure the mass and the volume of a quantity of water and then heat the water to various temperatures in the range using a thermometer to measure the temperature. They then attempt to determine the density of the water at the different temperatures. Assume any changes of equipment or measuring tools due to temperature changes are negligible. Which of the following methods would allow the students to obtain data from which they could determine the change in density of the water at different temperatures?
- ASubmerge a metal cylinder of known density in the water. Record precise measurements of the change in volume of the water due to the cylinder.
- BRecord the mass of the water and precise measurements of the volume of the water.
- CRecord the temperature of the water and precise measurements of the volume of the water.
- DRecord the temperature of the water and precise measurements of the mass of the water.
4In an experiment, a student puts each of three objects, A, B, and C, in four different liquids and observes whether the objects float. The results are listed in the table. Which columns contain information that is most useful for estimating the density of object C?
- AGasoline and Salt Water
- BGasoline and Oil
- CDistilled Water and Oil
- DDistilled Water and Salt Water
5A physics teacher gives a solid object to each student in her class. The objects are each made of the same material but have different shapes and sizes. The teacher asks the students to measure the mass and volume of their object and to work together to determine the density of the material from which the objects are made. Which of the following methods will give the best estimate of the material’s density?
- AEach student divides the mass of the object by its volume and shares the results with the class. The class then computes the average of all the densities.
- BEach student shares the mass and volume of their object with the class. The class then computes the average of the mass values and divides this by the average of the volume values.
- CEach student shares the mass and volume of their object with the class. The class then creates a graph plotting mass as a function of volume, draws a best-fit line through the data, and uses the slope of the best-fit line as the density of the material.
- DEach student shares the mass and volume of their object with the class. The class then creates a graph plotting mass as a function of volume, draws a best-fit line through the data, picks the data point closest to the line, and divides the mass for that point by its volume to compute the density of the material.
6Water is poured into a U-shaped tube and allowed to come to rest, as shown in the figure. Which of the following can help explain why the water in the left and right sides of the tube reaches the same height? Select two answers.
- AThe force exerted by the atmosphere on the surface of the water is the same on both sides.
- BThe average speed of the water molecules on both sides is the same.
- CThe surface tension of the water on both sides is the same.
- DThe weight of water in the left and right halves of the tube is the same.
7A wooden cube is floating at rest on the surface of a liquid. Which of the following is an action-reaction pair of forces that can explain why the force exerted by the liquid on the bottom of the container is greater with the floating cube than without it?
- AEarth exerts a gravitational force on the cube, and the liquid exerts a net upward force on the cube.
- BThe liquid exerts a net upward force on the cube, and the cube exerts a contact force on the liquid.
- CEarth exerts a gravitational force on the cube, and the cube exerts a gravitational force on Earth.
- DEarth exerts a gravitational force on the liquid, and the liquid exerts a net upward force on the cube.
8A block of weight (W) is floating in water, and one-third of the block is above the surface of the water. Which of the following correctly describes the magnitude (F) of the force that the block exerts on the water and explains why (F) has that value?
- AF= (2/3)*W. Only two-thirds of the block is in contact with the water, so it will exert a force on the water equal to two-thirds of the block’s weight.
- BF= (2/3)*W. The water exerts a force on the block equal to the weight of the part of the block that is underwater. The block then exerts a force of equal magnitude on the water.
- CF=W. The block is at rest, so the net force on it must be zero. The water must exert an upward force of magnitude (F) on the block to make this so. The block then exerts a force of equal magnitude on the water.
- DF=W. Any object will always exert a force on the surface beneath it that is equal to the weight of the object.
9A cube submerged in a rectangular tank of liquid is at rest. Which of the following is a Newton’s third law pair of forces in this situation?
- AThe force that the liquid exerts on a side of the tank and the force the liquid exerts on a side of the cube
- BThe force that the liquid exerts on a side of the tank and the force the side of the tank exerts on the liquid
- CThe force that the liquid exerts on the top of the cube and the force the liquid exerts on the bottom of the cube
- DThe force that the bottom of the cube exerts on the liquid and the force the liquid exerts on the bottom of the tank
10The figure shows a block of wood floating in a beaker of water. Which of the following is true of the force exerted by the wood on the water?
- AThe wood exerts a downward force on the water that is equal in magnitude to the upward force exerted by the beaker on the water.
- BThe wood exerts a downward force on the water that is equal in magnitude to the weight of the wood.
- CThe wood exerts an upward force on the water that is equal in magnitude to the weight of the displaced water.
- DThe wood does not exert a force on the water.
11A block of mass (M) is floating in a container of liquid and is partially submerged. The block is then replaced by a block of mass 2(M). Which of the following describes two forces that are a Newton's-third-law force pair whose magnitudes are the same for the two situations?
- AThe gravitational force Earth exerts on a block and the gravitational force a block exerts on Earth
- BThe gravitational force Earth exerts on the liquid and the gravitational force the liquid exerts on Earth
- CThe force the liquid exerts on the bottom of the container and the force the bottom of the container exerts on the liquid
- DThe force the liquid exerts on a block and the force a block exerts on the liquid
12A sphere made of gold is moving downward through liquid mercury at an increasing speed. The mercury exerts a net buoyant force in the upward direction on the gold sphere. Which of the following describes a Newton’s-third-law pair for this force?
- AThe gold sphere exerts a force on the mercury with magnitude equal to the weight of the gold sphere.
- BThe gold sphere exerts a force on the mercury with magnitude equal to the buoyant force.
- CEarth exerts a gravitational force on the gold sphere with magnitude equal to the weight of the gold sphere.
- DThe mercury exerts a frictional force on the gold sphere with magnitude equal to the weight of the gold sphere.
13A submarine of mass 3.6×10^6 kg is submerged in water and at equilibrium. Inside of the submarine are ballast tanks filled with water. Some of the water in the ballast tanks is then ejected, decreasing the density of the submarine. The free-body diagram in the figure shows the magnitude and direction of the forces acting on the submarine after the water is ejected. The acceleration of the submarine is most nearly
- A0.10 m/s^2
- B0.11 m/s^2
- C0.40 m/s^2
- D1.1 m/s^2
14A sphere of mass 0.5 kg is dropped into a column of oil. At the instant the sphere becomes completely submerged in the oil, the sphere is moving downward at 8 m/s, the buoyancy force on the sphere is 4.0 N, and the fluid frictional force is 4.0 N. Which of the following describes the motion of the sphere at this instant?
- AThe sphere’s speed is decreasing while the sphere continues to move downward.
- BThe sphere is moving downward at a constant speed.
- CThe sphere’s speed is increasing while the sphere continues to move downward.
- DThe sphere’s speed is increasing as the sphere begins moving upward.
15A solid cube is submerged in a container of water of density (ρw). The cube has mass M, volume (Vc), and density (ρw)/2. The water exerts an upward buoyant force on the cube of magnitude (ρw)(Vc)(g).
Which of the diagrams is the best representation of the forces exerted by the water on the cube?
- Aa
- Bb
- Cc
- Dd
- Aa
16A solid cube is submerged in a container of water of density (ρw). The cube has mass M, volume (Vc), and density (ρw)/2. The water exerts an upward buoyant force on the cube of magnitude (ρw)(Vc)(g).
The cube is released and allowed to rise. What is the magnitude of the acceleration of the cube immediately after release?- A1/2 g
- Bg
- C3/2 g
- D3g
17A solid cube is submerged in a container of water of density (ρw). The cube has mass M, volume (Vc), and density (ρw)/2. The water exerts an upward buoyant force on the cube of magnitude (ρw)(Vc)(g).
A solid sphere with unknown mass and twice the volume of the cube is submerged and then released. The sphere is observed to have the same acceleration immediately after release as the original cube. Which of the following claims can be made about the density of the sphere?- AThe density of the sphere must be twice that of the cube because the sphere's volume is twice as large as the cube.
- BThe density of the sphere must be half that of the cube because in order to have the same acceleration, the sphere and cube must have the same mass.
- CThe density of the sphere must be the same as that of the cube because in order to have the same acceleration, the sphere's mass must be twice the mass of the cube.
- DThe density of the sphere cannot be determined without knowing the mass of the sphere.
18In the lab, a student is given a glass beaker filled with water with an ice cube of mass (m) and volume (Vc) floating in it.
The ice cube displaces a volume (Vd) of water as it floats. The density of the water is (ρw), and the density of the ice is (ρi). The water exerts an upward buoyant force of magnitude (ρw)(Vd)(g) on the ice cube. Which of the following is equal to the magnitude of the force that the ice cube exerts on the water?
- Adensity of water*displaced volume*gravity
(pw)(Vd)(g) - Bdensity of ice*displaced volume*gravity
(pi)(Vd)(g) - Cdensity of water*volume of ice cube*gravity
(pw)(Vc)(g) - Ddensity of water*(volume of ice cube - displaced volume)*gravity
(pw)(Vc - Vd)(g)
- Adensity of water*displaced volume*gravity
19In the lab, a student is given a glass beaker filled with water with an ice cube of mass (m) and volume (Vc) floating in it.
The downward force of gravity on the ice cube has magnitude (Fg). The student pushes down on the ice cube with a force of magnitude (FP) so that the cube is totally submerged. The water then exerts an upward buoyant force on the ice cube of magnitude (FB). Which of the following is an expression for the magnitude of the acceleration of the ice cube when it is released?
- Aa
- Bb
- Cc
- Dd
- Aa
20A 1.0 m by 2.0 m by 3.0 m rectangular block has a uniform density of 600kg/m^3 and is completely submerged and held stationary in a deep pool of water. The water exerts an upward buoyant force on the block of 6×10^4 N . The block is released and, after rising a short distance toward the surface, experiences a drag force of 2×10^4 N. The magnitude of the acceleration of the block at this instant is most nearly
- A32.2 m/s^2
- B16.7 m/s^2
- C6.7 m/s^2
- D1.11 m/s^2
21A sphere with density (ρs) and volume (V) is submerged in a fluid with density (ρf) , which exerts a buoyant force of magnitude (ρf)(V)(g) on the sphere. Immediately after being released from rest, the sphere moves upward with an acceleration of magnitude (a) . Which of the following changes would result in an acceleration with greater magnitude immediately after release?
- AReleasing the sphere closer to the surface of the fluid
- BIncreasing the density of the fluid
- CIncreasing the volume of the sphere but keeping its density constant
- DIncreasing the air pressure at the surface of the fluid
22A small submarine is underwater and moving horizontally at the same constant speed as the northward current in a straight, level section of a river. It releases a sensor that will float in the water. If resistance is negligible, what is the shape of the path followed by the sensor?
- AA straight vertical path
- BA straight horizontal path
- CA straight path toward the north and angled upward
- DA parabolic path toward the north and curving upward
23A sphere of metal is placed in a liquid. The sphere sinks with an acceleration less than (g) due to the vertical buoyant force (FB) exerted by the liquid and the gravitational force (Fg) on the sphere. Which of the following best represents these two forces?
- Aa
- Bb
- Cc
- Dd
- Aa
24A sphere is moving vertically in a liquid. The free-body diagram shows the magnitudes and directions of the forces exerted on the sphere at a particular instant. What is the magnitude of the sphere’s acceleration and the direction of the sphere’s motion?
- Aa
- Bb
- Cc
- Dd
- Aa
25A block is submerged in a container of water and remains at rest with the only forces exerted on it being gravity and forces exerted by the water. The force exerted by the water on the bottom of the block is greater than the force exerted by the water on the top of the block. Which of the following is an explanation of the microscopic cause of the difference in the forces?
- AThe block exerts a downward force on the water equal to the block’s weight.
- BThe net force exerted by the water on the block is equal in magnitude and opposite in direction to the force the block exerts on the water, as required by Newton’s third law.
- CThe molecules of water hitting the bottom of the block have a greater average speed than those hitting the top of the block, and thus they exert a greater force.
- DThe contact force between the water and the bottom of the block is fundamentally due to interatomic electric forces.
26Four cubes with equal volumes are at rest in a container of water, as shown in the figure. A student claims that cube D is experiencing a greater number of water molecule collisions per second with its bottom surface than the other cubes. Which of the following indicates whether or not the student is correct and provides evidence?
- AThe student is correct, because the bottom surface of cube D is deepest, which means the pressure is greatest.
- BThe student is correct, because cube D is the most massive cube and therefore exerts the largest gravitational forces on the water molecules.
- CThe student is incorrect, because cube C is the furthest out of the water, so the pressure on the bottom of its surface is greatest.
- DThe student is incorrect, because the cubes all have the same volume, so they experience the same number of collisions per second.
27Two metal cylinders of equal density and volume are submerged in water and remain at rest with their top surfaces at the same height, as shown. Cylinder A has a smaller height and a larger cross-sectional area than cylinder B. Which of the following explains why the force exerted on the top of cylinder A is greater than the force exerted on the top of cylinder B?
- AThe water molecules striking the bottom surface of cylinder A have a greater average speed than the water molecules striking the bottom surface of cylinder B , so the force on the top of cylinder A must be greater to compensate.
- BThe water molecules striking the top surface of cylinder A have the same average speed as the water molecules striking the top surface of cylinder B , but more water molecules strike the top surface of cylinder A than the top surface of cylinder B .
- CThe difference in the average speed of the water molecules striking the top surface and bottom surface of cylinder A is less than that of cylinder B .
- DThe difference in the number of the molecules striking the top surface and bottom surface of cylinder A per unit time is less than that of cylinder B .
28The small dots in the figure represent the molecules of a solid object, and the dashed lines represent the molecular bonds between them. The large dots represent the molecules of a liquid in which the object floats. Which of the following best describes the force that explains the interaction of the object and the liquid?
- AGravitational attraction between all the molecules present
- BAn electrical force that repels the electrons of the object’s molecules from the electrons of the liquid’s molecules
- CMolecular bonds between the molecules of the object and the molecules of liquid
- DA strong nuclear force that causes repulsion between the molecules of the solid and the molecules of the liquid
29An ideal fluid flows from left to right in the horizontal pipe shown in the figure. The fluid enters the left side of the pipe with speed (v), where the diameter of the pipe is (d). The pipe then narrows to a diameter of d/2.
What is the speed of the fluid in the narrow section of the pipe with diameter d/2?
- Av/4
- Bv/2
- C2v
- D4v
30An ideal fluid flows from left to right in the horizontal pipe shown in the figure. The fluid enters the left side of the pipe with speed (v), where the diameter of the pipe is (d). The pipe then narrows to a diameter of d/2.
Does the pressure of the fluid change as the pipe becomes narrower, and why or why not?- AYes, because the kinetic energy of the fluid changes but the total gravitational potential energy of the fluid-Earth system is constant.
- BYes, because there must be a compensation for the smaller surface area of the narrower pipe.
- CNo, because the atmospheric pressure at both ends of the pipe is constant.
- DNo, because both sections of the pipe are at the same height.
31A plastic bowl is floating in a sink full of water. Which of the following describes the microscopic cause of the buoyant force exerted on the bowl by the water?
- AGravitational attraction between the molecules of the bowl and the molecules of the water
- BElectrostatic attraction between the nuclei in the molecules in the bowl and the electrons in the molecules of the water
- CElectrostatic repulsion between the nuclei in the molecules in the bowl and the nuclei in the molecules of the water
- DElectrostatic repulsion between the electrons in the molecules in the bowl and the electrons in the molecules of the water
32A block is submerged in a container of fluid. Which of the following describes the microscopic cause of the force exerted on the bottom of the block by the fluid being greater than the force exerted on the top of the block by the fluid?
- AThe electrostatic force between the electrons in the molecules of the block and the electrons in the molecules of the fluid is greater at the bottom than at the top.
- BThe electrostatic force between the nuclei in the molecules of the block and the electrons in the molecules of the fluid is greater at the bottom than at the top.
- CThe electrostatic force between the nuclei in the molecules of the block and the nuclei in the molecules of the fluid is greater at the bottom than at the top.
- DThe gravitational force between the molecules of the block and the molecules of the fluid is greater at the bottom than at the top.
33The figure shows a horizontal pipe with sections with different cross-sectional areas. Small tubes extend from the top of each section. The cross-sectional area of the pipe at location C is half that at A, and the areas at A and D are the same. Water flows in the pipe from left to right. Which of the following correctly ranks the height h of the water in the tubes above the labeled locations?
- AhA = hB = hC = hD
- BhA > hB > hC > hD
- C(hA = hD) > hB > hC
- DhC > hB > (hA = hD)
34Which of the following graphs best represents the absolute pressure (Pabs) at a point in a liquid near Earth’s surface as a function of the depth (h) of the point below the surface of the liquid?
- Aa
- Bb
- Cc
- Dd
- Aa
35In the figure, water flows from a section of pipe with a smaller radius to a section of pipe with a larger radius. How do the pressure and velocity in the wider pipe compare to those in the narrower pipe?
- Aa
- Bb
- Cc
- Dd
- Aa
36The figure shows a container filled with water to a depth (d). The container has a hole a distance (y) above its bottom, allowing water to exit with an initially horizontal velocity. Which of the following correctly predicts and explains how the speed of the water as it exits the hole would change if the distance (y) above the bottom of the container increased?
- AThe speed would decrease because the water pressure at the depth of the hole would decrease.
- BThe speed would decrease because the air pressure just outside of the hole would decrease.
- CThe speed would increase because more gravitational potential energy is being converted to kinetic energy
- DThe speed would increase because there is more water below the hole pushing up on the water near the hole.
37The figure shows a top view of three connected, horizontal pipes. Water moves from left to right in pipe A and then divides when it reaches the junction with pipes B and C. Pipes B and C have the same diameter, which is less than half the diameter of pipe A. Which of the following are correct statements about properties of the water? Select two answers.
- AThe gravitational potential energy of the water-Earth system is the same in all three pipes because they are at the same height.
- BThe kinetic energy of the water is the same in all three pipes because the rate of mass flow is the same everywhere.
- CThe kinetic energy of the water is the same in pipes B and C because they have the same diameter.
- DThe pressure of the water is the same in all three pipes because they are connected and form one system.
38The figure shows a horizontal pipe with sections with different cross-sectional areas. The cross-sectional area of the pipe at location C is half that at A, and the cross-sectional areas at A and D are the same. Water flows in the pipe from left to right. Which of the following correctly ranks the mass flow rate (f) in the four sections of pipe?
- AfA = fB = fC = fD
- B(fA = fD) > fB > fC
- CfC > fB > (fA = fD)
- DfA > fB > fC > fD
39An incompressible fluid is flowing in a pipe from point A to point B, as shown in the figure. The pipe is circular with a radius of 2cm at point A and a radius of 1cm at point B. The speed of the fluid at point A is (vA). Which of the following best describes the speed (vB) of the fluid at point B?
- A(vB) is greater than (vA) by a factor of 4, which is the ratio of the cross-sectional area at point A to the cross-sectional area at point B .
- B(vB) is less than (vA) by a factor of 4, which is the ratio of the cross-sectional area at point B to the cross-sectional area at point A .
- C(vB) is equal to (vA) because the fluid along the centerline of the pipe does not come into contact with the walls of the pipe.
- D(vB) is equal to (vA) because although the pipe becomes narrower, the density of the fluid remains constant, because the fluid is incompressible.
40The water coming out of a water fountain initially makes a 45° angle to the horizontal. Which of the following changes, if any, could result in the water reaching the ground farther from the fountain without changing the water pressure in the fountain pipe, and why?
- AIncreasing the angle of the fountain to be greater than 45° , because the time of flight of the water will increase.
- BUsing warmer water, because it will make the kinetic energy of the water greater.
- CUsing a smaller nozzle on the end of the fountain, because the smaller area of the opening will lead to a higher speed for the water.
- DRaising the fountain higher above the ground, because the water will travel farther horizontally when it has a greater vertical distance to fall.
41Water with density 1000 kg/m^3 is moving at 0.50 m/s through a cylindrical tube with a diameter of 0.10 m. The tube then narrows to a diameter of 0.05 m. The mass flow rate in the narrow section of pipe is most nearly
- A1.25 kg/s
- B3.9 kg/s
- C15.7 kg/s
- D50.0 kg/s
42A fountain in a park shoots a stream of water at an angle. Initially the stream reaches a height H and travels a horizontal distance D before hitting the ground. Over time, minerals in the water are deposited around the edges of the fountain opening, making it smaller. Which of the following describes the height and horizontal distance of the stream of water from the fountain at some later time?
- Aa
- Bb
- Cc
- Dd
- Aa
Información
- Descripción
- 12th grade Physics Test sobre Physics Fluid Test , creado por Riku Kear el 15/09/2022.
- Autor
- Riku Kear
- Idioma
- English
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- 10
- Historial
- Creado el 15 sep 2022 · actualizado el 16 sep 2022
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