




Conceptual questions
Water is shot nearly vertically upward in a decorative fountain and the stream is observed to broaden as it rises. Conversely, a stream of water falling straight down from a faucet narrows. Explain why.
The mass of water that enters a crosssectional area must equal the amount that leaves. From the continuity equation, we know that the density times the area times the velocity must remain constant. Since the density of the water does not change, the velocity times the crosssectional area entering a region must equal the crosssectional area times the velocity leaving the region. Since the velocity of the fountain stream decreases as it rises due to gravity, the area must increase. Since the velocity of the faucet stream speeds up as it falls, the area must decrease.
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A tube with a narrow segment designed to enhance entrainment is called a
Venturi , such as shown below. Venturis are very commonly used in carburetors and aspirators. How does this structure bolster entrainment?
When the tube narrows, the fluid is forced to speed up, thanks to the continuity equation and the work done on the fluid. Where the tube is narrow, the pressure decreases. This means that the entrained fluid will be pushed into the narrow area.
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Some chimney pipes have a Tshape, with a crosspiece on top that helps draw up gases whenever there is even a slight breeze. Explain how this works in terms of Bernoulli’s principle.
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Is there a limit to the height to which an entrainment device can raise a fluid? Explain your answer.
The work done by pressure can be used to increase the kinetic energy and to gain potential energy. As the height becomes larger, there is less energy left to give to kinetic energy. Eventually, there will be a maximum height that cannot be overcome.
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Roofs are sometimes pushed off vertically during a tropical cyclone, and buildings sometimes explode outward when hit by a tornado. Use Bernoulli’s principle to explain these phenomena.
Because of the speed of the air outside the building, the pressure outside the house decreases. The greater pressure inside the building can essentially blow off the roof or cause the building to explode.
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It is dangerous to stand close to railroad tracks when a rapidly moving commuter train passes. Explain why atmospheric pressure would push you toward the moving train.
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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 air inside the hose has kinetic energy due to its motion. The kinetic energy can be used to do work against the pressure difference.
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Questions & Answers
y oxygen is shift to first place
Angular accelaration force,as the result of the rotatation of earth
Arzoodan
Due to the rotation of the earth the winds at the equator get deflected in opposite direction and therefore cause some currents in the Northern and Southern hemisphere which are opposite in there spin.
Varsha
if cos = x/y then sec = y/x
if sin = y/x then cosec = x/y
if cosβ=x/y then what is cosecβ
. if cosβ=x/y what is cosecβ
Abubakar
if cosΦ=x/y what is cosecΦ
Abubakar
What are the unknown symbols?
Jan
It is defined that cosec = 1/sin and sec = 1/cos
Jan
Do you understand this?
Jan
∇(f/g) = (g∇f − f∇g)/g^2
, at points x where g(x) 6= 0 please help me to solve the problem ....
sir please add answer sheet of spigel vector analysis ..
In a pulley system 2 boxes r hanging in both sides of pulley. An other box was joined to the left box through a rope & get accelerated downward. If all the boxes have same mass ,then what will be the acceleration of that system ?
∇(f/g) = (g∇f − f∇g)/g2
, at points x where g(x) 6= 0 plus solve it
11
is the product of mass to it's velocity (mv)
Ahmed
quatity of motion present in a body
or
product of mass and velocity
Shakeel
the energy................................................
Rika
dont know want to know the answer
Rika
it's the product of mass multiplied by velocity
harsha
the quantity of motion possessed by a body is called its momentum.by virtue of which a body can exert a force in the agency which tend to stop it .it is a common experience that stronger force is required to stop more massive body.also faster the body moves harder it is to stop it .this is why
Manoj
momentum is product of mass and velocity and it is denoted by "P".
Manoj
show that the cross product of vector axb=bxa
Nature of the physical low
1/2 mv2 =mgh prove that
Rashika
study work energy theorem properly
Rohan
v2=u2+2gh...u=0...so 1/2 mv2=1/2m(2gh)=mgh
Talha
how can I become confident in physics
practice more and more question ,,,,if u get trouble in any one question infact do that again and again.
jyotirmayee
is theory important or numericals
arshdeep
both ,,,,because without understanding theory ,,,,u can't able to solve problemsss or numericals
jyotirmayee
which books I can follow for IIT jee prep for mcq and which for mcq
arshdeep
what can make me good in physics
lovet
how can I solve qsns in physics cuz I understand most of the theories but facing problem during solving the qsns.
Rohan
what can make me good in physics
Rika
Can someone please tell what really happened to planet Pluto
Pluto was consider as a dwarf planet and not a planet
a planet should satisfy the three criteria viz.it should have a orbit around the sun,it should be spherical in shap,and it should clear its orbit .
since,Pluto satisfy the first two criteria so it was not considered as a planet .
Manoj
but it was seen that earth also not cleared its orbit but earth is a planet so another criteria was made that a planet should have grater gravitational force other than its orbit and earth follow this but Pluto wasn't satisfied this criteria .so Pluto wasn't consider as a planet.since it follow the
Manoj
first two criteria so it gets a another name called dwarf planet
Manoj
what are the first 20 elements in periodic table.
what happened to the rest now, or have you forgotten?
Ejiba
Hydrozen helium lithium berrilium boron carbon nitrogen oxygen flourine neon sodium magnesium aluminium silicon phosphorous sulphur chlorine argon potassium calcium
Rika
you said 20 elements and thats here
Rika
excuse me any one here
Rika
it is the product of mass and velocity
harsha
momentum p = mass X velocity
harsha
Hydration energy?
osobase
The heat energy released when new bonds are made between the ions and water molecules is known as the hydration enthalpy of the ion
harsha
hydration energy is also called as hydration enthalpy.
harsha
yes what is hydration Energy?
osobase
Tripple point of water?
osobase
where water exists in all the three states
harsha
at that point it exists as water (liquid) , ice (solid) and vapours (gas)
harsha
What is d tripple point pressure of water?
osobase
I can't remember the exact number
harsha
76 cm of Hg = 1 bar
harsha
calculate it for 6millibar
harsha
what is hydrodynamics
Manoj
the branch of physics that deal with the motion of fluids and the force acting on a solid body immersed in it .
fluids means a substance that has no fixed shape and yields easily to external pressure viz.gas or liquid in other words a substance that able to flow easily.
Manoj
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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