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David rolled down the window on his car while driving on the freeway. An empty plastic bag on the floor promptly flew out the window. Explain why.

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Based on Bernoulli’s equation, what are three forms of energy in a fluid? (Note that these forms are conservative, unlike heat transfer and other dissipative forms not included in Bernoulli’s equation.)

Potential energy due to position, kinetic energy due to velocity, and the work done by a pressure difference.

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The old rubber boot shown below has two leaks. To what maximum height can the water squirt from Leak 1? How does the velocity of water emerging from Leak 2 differ from that of Leak 1? Explain your responses in terms of energy.

Figure is a drawing of a boot with two leaks located at the same height. Leak 1 points up while leak two points horizontally.
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Water pressure inside a hose nozzle can be less than atmospheric pressure due to the Bernoulli effect. Explain in terms of energy how the water can emerge from the nozzle against the opposing atmospheric pressure.

The water has kinetic energy due to its motion. This energy can be converted into work against the difference in pressure.

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Verify that pressure has units of energy per unit volume.

F = p A p = F A , [ p ] = N/m 2 = N · m/m 3 = J/m 3 = energy/volume

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Suppose you have a wind speed gauge like the pitot tube shown in [link] . By what factor must wind speed increase to double the value of h in the manometer? Is this independent of the moving fluid and the fluid in the manometer?

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If the pressure reading of your pitot tube is 15.0 mm Hg at a speed of 200 km/h, what will it be at 700 km/h at the same altitude?

−135 mm Hg

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Every few years, winds in Boulder, Colorado, attain sustained speeds of 45.0 m/s (about 100 mph) when the jet stream descends during early spring. Approximately what is the force due to the Bernoulli equation on a roof having an area of 220 m 2 ? Typical air density in Boulder is 1.14 kg/m 3 , and the corresponding atmospheric pressure is 8.89 × 10 4 N/m 2 . (Bernoulli’s principle as stated in the text assumes laminar flow. Using the principle here produces only an approximate result, because there is significant turbulence.)

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What is the pressure drop due to the Bernoulli Effect as water goes into a 3.00-cm-diameter nozzle from a 9.00-cm-diameter fire hose while carrying a flow of 40.0 L/s? (b) To what maximum height above the nozzle can this water rise? (The actual height will be significantly smaller due to air resistance.)

a. 1.58 × 10 6 N/m 2 ; b. 163 m

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(a) Using Bernoulli’s equation, show that the measured fluid speed v for a pitot tube, like the one in [link] (b), is given by v = ( 2 ρ g h ρ ) 1 / 2 , where h is the height of the manometer fluid, ρ is the density of the manometer fluid, ρ is the density of the moving fluid, and g is the acceleration due to gravity. (Note that v is indeed proportional to the square root of h , as stated in the text.) (b) Calculate v for moving air if a mercury manometer’s h is 0.200 m.

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A container of water has a cross-sectional area of A = 0.1 m 2 . A piston sits on top of the water (see the following figure). There is a spout located 0.15 m from the bottom of the tank, open to the atmosphere, and a stream of water exits the spout. The cross sectional area of the spout is A s = 7.0 × 10 −4 m 2 . (a) What is the velocity of the water as it leaves the spout? (b) If the opening of the spout is located 1.5 m above the ground, how far from the spout does the water hit the floor? Ignore all friction and dissipative forces.

Figure is a schematic drawing of a cylinder filled with fluid and opened to the atmosphere on one side. A disk of mass 20 kg and surface area A identical to the surface area of the cylinder, is placed in the fluid. It is a half meter above the bottom of the container. A spout, that is open to the atmosphere, is located 0.15 m from the bottom of the tank.

a. v 2 = 3.28 m s ;
b. t = 0.55 s
x = v t = 1.81 m

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A fluid of a constant density flows through a reduction in a pipe. Find an equation for the change in pressure, in terms of v 1 , A 1 , A 2 , and the density.

Figure is the schematic of a pipeline that narrows from the cross section area A1 to the cross section area A2. Fluid flows through the pipeline. Pressure and fluid velocity is different in the different parts of pipeline. They are P1 and v1 in the wide cross-section and P2 and v2 in the narrow cross section regions.
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Questions & Answers

Hi all, love you all!!!
Giorgi Reply
How does resonance occur
Rahim Reply
what is quantam
pamit Reply
quantum is a division of mechanics
what is friction
Muhammad Reply
a force act by surface between two bodies whose are always oppose the relative motion .....
when two rough bodies are placed in contact and try to slip each other ... than a force act them and it's ippse the relative motion between them
thats friction force and roughnes of both bodies is define friction of surface
what is a progressive wave
sheriff-deen Reply
What is the wake for therapist
Ife Reply
can u like explain your question with clear detail
who would teach me vectors?
Tintin Reply
what's chemistry
Esther Reply
branch of science dt deals with the study of physical properties of matter and it's particulate nature
Y acctually do u hav ur way of defining it? just bring ur iwn idear
well, it deals with the weight of substances and reaction behind them as well as the behavior
buh hope Esther, we've answered ur question
what's ohms law
ohms law states that, the current flowing through an electric circuit is directly proportional to the potential difference, provided temperature and pressure are kept constant
what is sound
ohms law states that the resistance of a material is directly proportional to the potential difference between two points on that material, if temperature and other physical conditions become constant
How do I access the MCQ
Abraham Reply
As I think the best is, first select the easiest questions for you .and then you can answer the remaining questions.
I mean I'm unable to view it
when I click on it, it doesn't respond
ohhh,try again and again ,It will be showed
what is centripetal force
Don Reply
هي قوة ناتجة من الحركة الدائرية ويكون اتجاهها إلى المركز دائماً
meaning of vector quantity
Felix Reply
vector quantity is any quantity that has both magnitude in terms of number (units) and direction in terms of viewing the quantity from an origin using angles (degree) or (NEWS) method
vector quantity is physical quantity has magnitude and direction
vector is a quantity that is use in measuring size of physical properties and their direction
what difference and similarities between work,force,energy and power?
Anes Reply
I need the best answer
enery is the ability to do work. work is job done, force is a pull or push. power has to do with potential. they belong to different categories which include heat energy, electricity.
force refers to a push or pull... energy refers to work done while power is work done per unit time
mathematically express angular velocity and angular acceleration
Mario Reply
it depends on the direction. an angular velocity will be linear and angular acceleration will be an angle of elevation.
The sonic range finder discussed in the preceding question often needs to be calibrated. During the calibration, the software asks for the room temperature. Why do you suppose the room temperature is required?
Shaina Reply
Suppose a bat uses sound echoes to locate its insect prey, 3.00 m away. (See [link] .) (a) Calculate the echo times for temperatures of 5.00°C5.00°C and 35.0°C.35.0°C. (b) What percent uncertainty does this cause for the bat in locating the insect? (c) Discuss the significance of this uncertainty an
give a reason why musicians commonly bring their wind instruments to room temperature before playing them.
The ear canal resonates like a tube closed at one end. (See [link]Figure 17_03_HumEar[/link].) If ear canals range in length from 1.80 to 2.60 cm in an average population, what is the range of fundamental resonant frequencies? Take air temperature to be 37.0°C,37.0°C, which is the same as body tempe
By what fraction will the frequencies produced by a wind instrument change when air temperature goes from 10.0°C10.0°C to 30.0°C30.0°C ? That is, find the ratio of the frequencies at those temperatures.
what are vector quantity
Aondover Reply
Quantities that has both magnitude and direction
what is lenses
vector quantities are those physical quantites which have magnitude as well as direction and obey the laws of vector algebra.
electric current has both magnitude and direction but it doesn't obey the laws of vector algebra, hence it is not a vector quantity.
Practice Key Terms 2

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Source:  OpenStax, University physics volume 1. OpenStax CNX. Sep 19, 2016 Download for free at http://cnx.org/content/col12031/1.5
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