Question 1

Mercury is a convenient liquid to use in a barometer because:

Accepted Answer

A)  it is a metal 
B)  it has a high boiling point 
C)  it expands little with temperature 
D)  it has a high density 
E)  it looks silvery 
A)  it is a metal 
B)  it has a high boiling point 
C)  it expands little with temperature 
D)  it has a high density 
E)  it looks silvery

Question 2

One end of a cylindrical pipe has a radius of 1.5 cm. Water (density = 1.0 *103 kg/m3) streams steadily out at 7.0 m/s. The volume flow rate is:

Accepted Answer

A)  4.9 * 10-3 m3/s 
B)  2.5 m3/s 
C)  4.9 m3/s 
D)  7.0 m3/s 
E)  48 m3/s 
A)  4.9 * 10-3 m3/s 
B)  2.5 m3/s 
C)  4.9 m3/s 
D)  7.0 m3/s 
E)  48 m3/s

Question 3

The pressure exerted on the ground by a man is greatest when:

Accepted Answer

A)  he stands with both feet flat on the ground 
B)  he stands flat on one foot 
C)  he stands on the toes of one foot 
D)  he lies down on the ground 
E)  all of the above yield the same pressure 
A)  he stands with both feet flat on the ground 
B)  he stands flat on one foot 
C)  he stands on the toes of one foot 
D)  he lies down on the ground 
E)  all of the above yield the same pressure

Question 4

The units of pressure can also be written as:

Accepted Answer

A)  N/m 
B)  J∙m2 
C)  W/m2 
D)  J/m3 
E)  N/m3 
A)  N/m 
B)  J∙m2 
C)  W/m2 
D)  J/m3 
E)  N/m3

Question 5

A uniform U-tube is partially filled with water. Oil, of density 0.75 g/cm3, is poured into the right arm until the water level in the left arm rises 3 cm. The length of the oil column is then:

Accepted Answer

A)  2.25 cm 
B)  8 cm 
C)  6 cm 
D)  4 cm 
E)  need to know the cross-sectional area of the U-tube 
A)  2.25 cm 
B)  8 cm 
C)  6 cm 
D)  4 cm 
E)  need to know the cross-sectional area of the U-tube

Question 6

A U-tube has dissimilar arms, one having twice the diameter of the other. It contains an incompressible fluid and is fitted with a sliding piston in each arm, with each piston in contact with the fluid. When an applied force does work W in pushing the piston in the narrow arm down, the fluid does work __________ on the piston in the wide arm.

Accepted Answer

A)  W 
B)  2W 
C)  W/2 
D)  4W 
E)  W/4 
A)  W 
B)  2W 
C)  W/2 
D)  4W 
E)  W/4

Question 7

A large tank filled with water has two holes in the bottom, one with twice the radius of the other. In steady flow the speed of water leaving the larger hole is ________ the speed of the water leaving the smaller.

Accepted Answer

A)  twice 
B)  four times 
C)  half 
D)  one-fourth 
E)  the same as 
A)  twice 
B)  four times 
C)  half 
D)  one-fourth 
E)  the same as

Question 8

A closed hemispherical shell of radius R is filled with fluid at uniform pressure p. The net force of the fluid on the curved portion of the shell is given by:

Accepted Answer

A)  2 $\pi$R2p 
B)   $\pi$R2p 
C)  4 $\pi$R2p 
D)  (4/3) $\pi$R2p 
E)  (4/3) $\pi$R3p 
A)  2 $\pi$R2p 
B)   $\pi$R2p 
C)  4 $\pi$R2p 
D)  (4/3) $\pi$R2p 
E)  (4/3) $\pi$R3p

Question 9

A block of ice at 0 $\degree$C containing a piece of cork is floating on the surface of water in a beaker. When the ice has melted the water level:

Accepted Answer

A)  is higher 
B)  is lower 
C)  is the same 
D)  depends on the initial ratio of water to ice 
E)  depends on the shape of the ice block 
A)  is higher 
B)  is lower 
C)  is the same 
D)  depends on the initial ratio of water to ice 
E)  depends on the shape of the ice block

Question 10

A large water tank, open at the top, has a small hole in the bottom. When the water level is 30 m above the bottom of the tank, the speed of the water leaking from the hole:

Accepted Answer

A)  is 2.5 m/s 
B)  is 24 m/s 
C)  is 44 m/s 
D)  cannot be calculated unless the area of the hole is given 
E)  cannot be calculated unless the areas of the hole and tank are given 
A)  is 2.5 m/s 
B)  is 24 m/s 
C)  is 44 m/s 
D)  cannot be calculated unless the area of the hole is given 
E)  cannot be calculated unless the areas of the hole and tank are given

Question 11

An open-tube manometer is used to measure the gauge pressure in a tank. If the manometer is filled with mercury, and the open end is at a height of 15 cm above the end attached to the tank, what is the gauge pressure in the tank? The density of mercury is 14 x 103 kg/m3.

Accepted Answer

A)  2.1 x 103 Pa 
B)  2.1 x 104 Pa 
C)  4.0 x 104 Pa 
D)  1.2 x 105 Pa 
E)  2.1 x 106 Pa 
A)  2.1 x 103 Pa 
B)  2.1 x 104 Pa 
C)  4.0 x 104 Pa 
D)  1.2 x 105 Pa 
E)  2.1 x 106 Pa

Question 12

Barometers and open-tube manometers are two instruments that are used to measure pressure. Which statement is true?

Accepted Answer

A)  Both measure gauge pressure 
B)  Both measure absolute pressure 
C)  Barometers measure gauge pressure and manometers measure absolute pressure 
D)  Barometers measure absolute pressure and manometers measure gauge pressure 
E)  Both measure an average of the absolute and gauge pressures 
A)  Both measure gauge pressure 
B)  Both measure absolute pressure 
C)  Barometers measure gauge pressure and manometers measure absolute pressure 
D)  Barometers measure absolute pressure and manometers measure gauge pressure 
E)  Both measure an average of the absolute and gauge pressures

Question 13

A cork floats on the surface of an incompressible liquid in a container exposed to atmospheric pressure. The container is then sealed and the air above the liquid is evacuated. The cork:

Accepted Answer

A)  sinks slightly 
B)  rises slightly 
C)  floats at the same height 
D)  bobs up and down about its old position 
E)  behaves erratically 
A)  sinks slightly 
B)  rises slightly 
C)  floats at the same height 
D)  bobs up and down about its old position 
E)  behaves erratically

Question 14

The quantity y appearing in Bernoulli's equation MUST be measured:

Accepted Answer

A)  upward from the center of the Earth 
B)  upward from the surface of the Earth 
C)  upward from the lowest point in the flow 
D)  downward from the highest point in the flow 
E)  upward from any convenient level 
A)  upward from the center of the Earth 
B)  upward from the surface of the Earth 
C)  upward from the lowest point in the flow 
D)  downward from the highest point in the flow 
E)  upward from any convenient level

Question 15

Two balls have the same shape and size but one is denser than the other. When they are dropped in air, which has the greater acceleration? Do not ignore air resistance.

Accepted Answer

A)  The heavier ball 
B)  The lighter ball 
C)  They have the same acceleration 
D)  The heavier ball if atmospheric pressure is high, they lighter ball if it is low 
E)  The lighter ball if atmospheric pressure is high, the heavier ball if it is low 
A)  The heavier ball 
B)  The lighter ball 
C)  They have the same acceleration 
D)  The heavier ball if atmospheric pressure is high, they lighter ball if it is low 
E)  The lighter ball if atmospheric pressure is high, the heavier ball if it is low

Question 16

A 210-g object apparently loses 30 g when suspended in a liquid of density 2.0 g/cm3. The density of the object is:

Accepted Answer

A)  7.0 g/cm3 
B)  3.5 g/cm3 
C)  1.4 g/cm3 
D)  14 g/cm3 
E)  none of these 
A)  7.0 g/cm3 
B)  3.5 g/cm3 
C)  1.4 g/cm3 
D)  14 g/cm3 
E)  none of these

Question 17

A fluid is undergoing "incompressible" flow. This means that:

Accepted Answer

A)  the pressure at a given point cannot change with time 
B)  the velocity at a given point cannot change with time 
C)  the velocity must be the same everywhere 
D)  the pressure must be the same everywhere 
E)  the density cannot change with time or location 
A)  the pressure at a given point cannot change with time 
B)  the velocity at a given point cannot change with time 
C)  the velocity must be the same everywhere 
D)  the pressure must be the same everywhere 
E)  the density cannot change with time or location

Question 18

A student standardizes the concentration of a salt-water solution by slowly adding salt until an egg will just float. The procedure is based on the assumption that:

Accepted Answer

A)  all eggs have the same volume 
B)  all eggs have the same weight 
C)  all eggs have the same density 
D)  all eggs have the same shape 
E)  the salt tends to neutralize the cholesterol in the egg 
A)  all eggs have the same volume 
B)  all eggs have the same weight 
C)  all eggs have the same density 
D)  all eggs have the same shape 
E)  the salt tends to neutralize the cholesterol in the egg

Question 19

One piston in a hydraulic lift has an area that is twice the area of the other. When the pressure at the smaller piston is increased by $\Delta$ p the pressure at the larger piston:

Accepted Answer

A)  increases by 2$\Delta$ p 
B)  increases by $\Delta$ p/2 
C)  increases by $\Delta$ p 
D)  increases by 4$\Delta$ p 
E)  does not change 
A)  increases by 2$\Delta$ p 
B)  increases by $\Delta$ p/2 
C)  increases by $\Delta$ p 
D)  increases by 4$\Delta$ p 
E)  does not change

Question 20

Which of the following assumptions is NOT made in the derivation of Bernoulli's equation?

Accepted Answer

A)  assume streamline flow 
B)  neglect viscosity 
C)  neglect friction 
D)  neglect gravity 
E)  neglect turbulence 
A)  assume streamline flow 
B)  neglect viscosity 
C)  neglect friction 
D)  neglect gravity 
E)  neglect turbulence

Exam 14: Fluids

Mercury is a convenient liquid to use in a barometer because:

One end of a cylindrical pipe has a radius of 1.5 cm. Water (density = 1.0 *103 kg/m3) streams steadily out at 7.0 m/s. The volume flow rate is:

The pressure exerted on the ground by a man is greatest when:

The units of pressure can also be written as:

A uniform U-tube is partially filled with water. Oil, of density 0.75 g/cm3, is poured into the right arm until the water level in the left arm rises 3 cm. The length of the oil column is then:

A large tank filled with water has two holes in the bottom, one with twice the radius of the other. In steady flow the speed of water leaving the larger hole is ________ the speed of the water leaving the smaller.

A closed hemispherical shell of radius R is filled with fluid at uniform pressure p. The net force of the fluid on the curved portion of the shell is given by:

A block of ice at 0 °\degree° C containing a piece of cork is floating on the surface of water in a beaker. When the ice has melted the water level:

A large water tank, open at the top, has a small hole in the bottom. When the water level is 30 m above the bottom of the tank, the speed of the water leaking from the hole:

An open-tube manometer is used to measure the gauge pressure in a tank. If the manometer is filled with mercury, and the open end is at a height of 15 cm above the end attached to the tank, what is the gauge pressure in the tank? The density of mercury is 14 x 103 kg/m3.

Barometers and open-tube manometers are two instruments that are used to measure pressure. Which statement is true?

A cork floats on the surface of an incompressible liquid in a container exposed to atmospheric pressure. The container is then sealed and the air above the liquid is evacuated. The cork:

The quantity y appearing in Bernoulli's equation MUST be measured:

Two balls have the same shape and size but one is denser than the other. When they are dropped in air, which has the greater acceleration? Do not ignore air resistance.

A 210-g object apparently loses 30 g when suspended in a liquid of density 2.0 g/cm3. The density of the object is:

A fluid is undergoing "incompressible" flow. This means that:

A student standardizes the concentration of a salt-water solution by slowly adding salt until an egg will just float. The procedure is based on the assumption that:

One piston in a hydraulic lift has an area that is twice the area of the other. When the pressure at the smaller piston is increased by Δ\DeltaΔ p the pressure at the larger piston:

Which of the following assumptions is NOT made in the derivation of Bernoulli's equation?

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One end of a cylindrical pipe has a radius of 1.5 cm. Water (density = 1.0 *10³ kg/m³) streams steadily out at 7.0 m/s. The volume flow rate is:

A uniform U-tube is partially filled with water. Oil, of density 0.75 g/cm³, is poured into the right arm until the water level in the left arm rises 3 cm. The length of the oil column is then:

A block of ice at 0 $\degree$ C containing a piece of cork is floating on the surface of water in a beaker. When the ice has melted the water level:

An open-tube manometer is used to measure the gauge pressure in a tank. If the manometer is filled with mercury, and the open end is at a height of 15 cm above the end attached to the tank, what is the gauge pressure in the tank? The density of mercury is 14 x 10³ kg/m³.

A 210-g object apparently loses 30 g when suspended in a liquid of density 2.0 g/cm³. The density of the object is:

One piston in a hydraulic lift has an area that is twice the area of the other. When the pressure at the smaller piston is increased by $\Delta$ p the pressure at the larger piston: