Physics chapter 11

Oil ( = 925 kg/m3) is flowing through a pipeline at a constant speed when it encounters a vertical bend in the pipe raising it 4.0 m. The cross sectional area of the pipe does not change. What is the difference in pressure (PB - PA) in the portions of the pipe before and after the rise

-3.6 x 10^4 Pa

A balloon inflated with helium gas (density = 0.2 kg/m3) has a volume of 6 × 10-3 m3. If the density of air is 1.3 kg/m3, what is the buoyant force exerted on the balloon?

0.08 N

The density of the liquid flowing through the horizontal pipe in the drawing is 1200 kg/m3. The speed of the fluid at point A is 7.5 m/s while at point B it is 11 m/s. What is the difference in pressure, PB - PA, between points B and A?

-3.9 x 10^4 Pa

What is the average force exerted by each nail on the professor's body?

0.398 N

A balloon is released from a tall building. The total mass of the balloon including the enclosed gas is 2.0 kg. Its volume is 5.0 m3. The density of air is 1.3 kg/m3. 39. What is the average density of the balloon?

0.4 kg/m^3

A horizontal piping system that delivers a constant flow of water is constructed from pipes with different diameters as shown in the figure. At which of the labeled points is the water in the pipe under the greatest pressure? The drawing is a view from above the pipe.

A

What is the total force exerted on the bottom of the swimming pool?

3.92 x 10^7 N

Water flows through a pipe of diameter 8.0 cm with a speed of 10.0 m/s. It then enters a smaller pipe of diameter 3.0 cm. What is the speed of the water as it flows through the smaller pipe?

71 m/s

A woman is enjoying a tropical drink while lying on a beach. The acceleration due to gravity at her location is 9.78 m/s2. What gauge pressure must exist in the woman's mouth if she is drinking through a straw extending 0.075 m above the surface of the drink? Note: Assume the drink has a density of 1020 kg/m3.

750 Pa

Within a certain type of star called a neutron star, the material at the center has a mass density of 1.0 × 1018 kg/m3. If a tiny sphere of this material of radius 1.0 × 10-5 m were somehow transported to the surface of the earth, what would be the weight of this sphere?

4.1 x 10^4 N

What is the total pressure at point A?

4.27 x 10^5 Pa

Using the value of atmospheric pressure at sea level, 1 × 105 Pa, estimate the total mass of the earth's atmosphere above a 5-m2 area.

5 x 10^4 kg

An object weighs 15 N in air and 13 N when submerged in mineral spirits, which has a density of 788 kg/m3. Determine the density of the object.

5.9 x 10^3 kg/m^3

What mass of water (at 4.0 °C) can be contained in a rectangular box whose dimensions are 10.0 cm by 5.00 cm by 1.00 cm? The density of water at 4.0 °C is 1.000 × 103 kg/m3.

50.0 g

An ice cube, p = 917 kg/m3, is sliding down a frictionless incline as shown in the drawing. The sides of the cube each have a length of 0.75 m. What pressure does the cube exert on the incline?

6500 Pa

The density of gold is 19 300 kg/m3. What is the mass of a gold sphere whose diameter is 0.25 m?

158 kg

At what speed is mercury flowing past the point labeled B?

8.57 m/s

One of the largest barometers ever built was an oil-filled barometer constructed in Leicester, England in 1991. The oil had a height of 12.2 m. Assuming a pressure of 1.013 × 105 Pa, what was the density of the oil used in the barometer?

847 kg/m^3

At a location where the acceleration due to gravity is 9.807 m/s2, the atmospheric pressure is 9.891 × 104 Pa. A barometer at the same location is filled with an unknown liquid. What is the density of the unknown liquid if its height in the barometer is 1.163 m?

8672 kg/m^3

A large tank is filled with water to a depth of 15 m. A spout located 10.0 m above the bottom of the tank is then opened as shown in the drawing. With what speed will water emerge from the spout?

9.9 m/s

A large vat is continually filled with a viscous liquid that flows from two equally long, cylindrical pipes, labeled A and B, onto a conveyer belt as shown in the drawing. The diameter of pipe B is 1.75 times larger than that of pipe A. What is the ratio of the average volume flow rate of the liquid exiting pipe B to that of the liquid exiting pipe A?

9.38

A pirate's treasure chest lies 20.0 m below the surface of the ocean. What is the magnitude of the force that acts on the rectangular top that is 0.750 m × 0.425 m?

9.48 x 10^4 N

In a car lift, compressed air with a gauge pressure of 4.0 × 105 Pa is used to raise a piston with a circular cross-sectional area. If the radius of the piston is 0.17 m, what is the maximum mass that can be raised using this piston?

3700 kg

A small sculpture made of brass ( brass = 8470 kg/m3) is believed to have a secret central cavity. The weight of the sculpture in air is 15.76 N. When it is submerged in water, the weight is 13.86 N. What is the volume of the secret cavity?

4 x 10^-6 m^3

At what speed is mercury flowing past the point labeled A?

4.0 m/s

How much force does the atmosphere exert on one side of a vertical wall 4.00-m high and 10.0-m long?

4.05 x 10^-6 N

A column of oil of height 70.0 cm supports a column of an unknown liquid as suggested in the figure (not drawn to scale). Assume that both liquids are at rest and that the density of the oil is 840 kg/m3. Determine the density of the unknown liquid

2.2 x 10^3 kg/m^3

A 2-kg block displaces 10 kg of water when it is held fully immersed. The object is then tied down as shown in the figure; and it displaces 5 kg of water. What is the tension in the string?

30 N

A gas sample is confined within a chamber that has a movable piston. A small load is placed on the piston; and the system is allowed to reach equilibrium. If the total weight of the piston and load is 70.0 N and the piston has an area of 5.0 × 10-4 m2, what is the pressure exerted on the piston by the gas? Note: Atmospheric pressure is 1.013 × 105 Pa.

2.4 x 10^5 Pa

What is the total pressure exerted on the bottom of the swimming pool?

1.31 x 10^5 Pa

The average density of the material in intergalactic space is approximately 2.5 × 10-27 kg/m3. What is the volume of a lead sample, = 11 300 kg/m3, that has the same mass as 8.0 × 1024 m3 of intergalactic space?

1.8 x 10^-6 m^3

The density of ice is 0.92 g/cm3; and the density of seawater is 1.03 g/cm3. A large iceberg floats in Arctic waters. What fraction of the volume of the iceberg is exposed?

11%

Selena uses a garden hose to fill a bucket of water. The water enters the hose through a faucet with a 6.0-cm diameter. The speed of the water at the faucet is 5 m/s. If the faucet and the nozzle are at the same height, and the water leaves the nozzle with a speed of 20 m/s, what is the diameter of the nozzle?

3.0 cm

Determine the density of the unknown liquid.

3.03 x 10^3 kg/m^3

If the area of contact at the head of each nail is 1.26 × 10-6 m2, what is the average pressure at each contact?

3.16 x 10^5 Pa

A hypodermic needle consists of a plunger of circular cross-section that slides inside a hollow cylindrical syringe. When the plunger is pushed, the contents of the syringe are forced through a hollow needle (also of circular cross-section). If a 4.0-N force is applied to the plunger and the diameters of the plunger and the needle are 1.2 cm and 2.5 mm, respectively, what force is needed to prevent fluid flow at the needle?

0.17 N

Water is flowing through a rectangular channel that is 12 m wide with a speed of 0.75 m/s. The water then flows into four identical rectangular channels that have a width of 3.0 m. The depth of the water does not change as it flows into the four channels. What is the speed of the water in one of the smaller channels?

0.75 m/s

At standard temperature and pressure, carbon dioxide has a density of 1.98 kg/m3. What volume does 1.70 kg of carbon dioxide occupy at standard temperature and pressure?

0.86 m^3

A child wants to pump up a bicycle tire so that its pressure is 1.2 × 105 Pa above that of atmospheric pressure. If the child uses a pump with a circular piston 0.035 m in diameter, what force must the child exert?

120 N

A force of 250 N is applied to a hydraulic jack piston that is 0.02 m in diameter. If the piston that supports the load has a diameter of 0.15 m, approximately how much mass can be lifted by the jack? Ignore any difference in height between the pistons.

1400 kg

A barometer is taken from the base to the top of a 279-m tower. Assuming the density of air is 1.29 kg/m3, what is the measured change in pressure?

3530 Pa

Elaine went to her outside faucet to fill a 0.0189-m3 bucket with water to wash her car. Water exits with a speed of 0.61 m/s. The radius of the faucet is 0.0078 m. How long does it take to fill the bucket completely?

160 s

When a block of volume 1.00 × 10-3 m3 is hung from a spring scale as shown in Figure A, the scale reads 10.0 N. When the same block is then placed in an unknown liquid, it floats with 2/3 of its volume submerged as suggested in Figure B. The density of water is 1.00 × 103 kg/m3. Determine the mass of the block.

2.02 kg

After a moving van drives onto a river ferry, the ferry sinks 0.0367 m. The length and width of the ferry are 15.24 m and 6.10 m, respectfully. Determine the weight of the moving van.

3.34 x 10^4 N

What is the total pressure at point B?

3.64 x 10^4 Pa

A solid cylinder has a radius of 0.051 m and a height of 0.0030 m. The cylinder is composed of two different materials with mass densities of 1950 kg/m3 and 1470 kg/m3. The cylinder contains an equal mass m of each of the two materials, so that the total mass is M = 2m. What is the mass m?

2.1 x 10^-2 kg

The density of mercury is 1.36 × 104 kg/m3. What is the mass of a 2.16 × 10-4-m3 sample of mercury?

2.94 kg

What is the magnitude of the initial acceleration of the balloon?

22.1 m/s^2

Determine the height h of mercury in the manometer with the evacuated upper end.

278 mm

What is the total pressure at point C?

1.01 x 10^5 Pa

Water enters a pipe of diameter 3.0 cm with a velocity of 3.0 m/s. The water encounters a constriction where its velocity is 15 m/s. What is the diameter of the constricted portion of the pipe?

1.3 cm

Complete the following statement: Bernoulli's principle is a statement of

energy conservation in dynamic fluids

Which one of the following statements concerning fluid streamlines is true?

in steady flow, the pattern of streamlines does not change with time

A curtain hangs straight down in front of an open window. A sudden gust of wind blows past the window; and the curtain is pulled out of the window. Which law, principle, or equation can be used to explain this movement of the curtain?

Bernoulli's equation

A u-shaped tube is connected to a flexible tube that has a membrane-covered funnel on the opposite end as shown in the drawing. Justin finds that no matter which way he orients to membrane, the height of the liquid in the u-shaped tube does not change. Which of the following choices best describes this behavior?

Pascal's principle

Complete the following sentence: The operation of a hydraulic jack is an application of

Pascal's principle

Which law, principle, or equation can be used to determine the volume flow rate of a liquid that is forced through a hypodermic needle?

Poiseulle's law

Using the notation given above, which one of the following sets of equations below is correct for this situation?

SA = SB and 2BA = BB

. Will the balloon rise, fall, or remain stationary; and why?

The balloon will rise because the upward bouyant force is greater than its weight

Which one of the following statements concerning the buoyant force on an object submerged in a liquid is true?

The bouyant force depends on the volume of the liquid displaced

The two dams are identical with the exception that the water reservoir behind dam A extends twice the horizontal distance behind it as that of dam B. Which one of the following statements regarding these dams is correct?

The horizontal distance ofthe water behind the two dams does not determine the force on them

Three blocks, labeled A, B, and C, are floating in water as shown in the drawing. Blocks A and B have the same mass and volume. Block C has the same volume, but is submerged to a greater depth than the other two blocks. Which one of the following statements concerning this situation is false?

The volume of water displaced by block A is greater than that displaced by block B

Which one of the following statements is false concerning the derivation or usage of Bernoulli's equation?

Vertical distances are always measured relative to the lowest point within the fluid

Which one of the following statements concerning a completely enclosed fluid is true?

any change in applied pressure produces an equal change in pressure at all points within the fluid

Which one of the following statements concerning streamline flow is true?

at any given point in the fluid, the velocity is constant in time