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  • 1 answers

Imran Khan 8 years, 10 months ago

For this questions you  will need some mathematics and knowledge of engineering thermodynamics. Appropriate links are provided at the bottom of this section. As we saw previously all Carnot heat engine have the same efficiency irrespective of the working gas we are using. Hence, we might as well use an ideal gas with temperature-independent specific heats because its properties are precisely known and can be represented in terms of fairly easy equations. All noble gases ( helium, neon, argon, krypton, xenon, and the radioactive radon ) come extremely close to being an ideal gas at temperatures and pressure relevant to Stirling engine.

(6)       p V = m Rs T         Ideal gas law

(7)       Δu = cv ΔT         Change of internal energy is proportional to change in temperature

<th>Figure 5 : Carnot Cycle</th>
  • 1 → 2 : isothermal compression.
    Because temperature is constant the internal energy of the gas does not change according to Eq.(2). According to Eq.(1) we also have <i>p V = m R Tc= constant</i>. This makes it possible to evaluate the work integral Wc =&int; p dV
    This results in the equation :

    (8)       Qc=Wc = m Rs Tc ln ( V1 / V2 )

  • 3 → 4 : isothermal expansion.
    This follows exactly the logic as the process 1 → 2. Hence,

    (9)       Qh=Wh = m Rs Th ln ( V4 / V3 )

  • 2 → 3 : adiabatic compression.
    With κ = cp/cv for such process :

    (10)       V2/V3 = (Th/Tc)1/(κ-1)

  • 4 → 1 : adiabatic expansion.
    Follows the same logic as process 2 → 3 with the result:

    (11)       V1/V4 = (Th/Tc)1/(κ-1)

We use Eq.(8) and (9) to find a first expression for the efficiency of the Carnot cycle (see also Eq.(3) ) :

(12)       η = 1 - Qc/Qh = 1 - (Tc ln ( V1 / V2 )) / (Th ln ( V4 / V3 ))

From Eq. (10) and (11) we get :

(13)       V1/V2 = V4/V3

and therefore :

(14)       η = 1 - Tc/Th

i hope that you will like it

  • 2 answers

Naveen Sharma 8 years, 10 months ago

Ans. Let two angles of projection for which the horizontal range is same are α and β.

Then the relation b/w them : α + β = 90°

Naveen Sharma 8 years, 10 months ago

 Let two angles of projection for which the horizontal range is same are α and β.Then the relation b/w them :α+β = 90°

 

  • 2 answers

Naveen Sharma 8 years, 10 months ago

Ans . Proof : Let the velocity, pressure and area of a fluid column at a point X be v1, p1and A1 

and at another point Y be v2, p2 and A2. Let the volume that is bounded by X and Y 

be moved to M and N. let XM = L1 and YN = L2. Now if we can compress the fluid then we have,

  A1 × L1= A2 × L2

We know that that the work done by the pressure difference per volume of the 

unit is equal to the sum of the gain in kinetic energy and 

gain in potential energy per volume of the unit.

This implies Work done = force × distance  Work done =  p × volume

Therefore, net work done per volume = p1  p2  

Also, kinetic energy per unit volume = 12 mv2 = 12 ρv2

Therefore, we have,

Kinetic energy gained per volume of unit = 12 ρv22 - v12

And potential energy gained per volume of unit = pg (h2  h1)

Here, h1 and h2 are heights of X and Y above the reference level taken in common.

Finally we have  p1  p2 = 12ρ v22-v12 + ρg (h2  h1)

  p1 + 12 ρ(v1)2 + ρgh1 = p2 + 12ρ (v2)2 + ρgh2

  p + 12ρv2 + ρgh is a constant  When we have h1 = h2  

Then we have, p + 12 ρv2is a constant.  This proves the Bernoullis Theorem

Naveen Sharma 8 years, 10 months ago

Ans. According to Bernoullis theorem in physics, whenever there is an increase in the speed of the liquid, there is a simultaneous decrease in the potential energy of the fluid or we can say that there is a decrease in the pressure of the fluid. Basically, it is a principle of conservation of energy in the case of ideal fluids. If the fluid flows horizontally such that there is no change in the gravitational potential energy of the fluid then increase in velocity of the fluid results in a decrease in pressure of the fluid and vice versa.

  • 1 answers

Naveen Sharma 8 years, 10 months ago

Ans. Lorentz Force is given by F = qv×B

as the force is always perpendicular to the motion and work done given by W = F.S cosθ, as angle is always 90 so work done will be Zero. 

  • 1 answers

Naveen Sharma 8 years, 10 months ago

Ans. a) The Average KE will be the Same as Conditions of temrature and pressure are same.

b) We know Vrms = 3pVM = 3RTM = 3RTmN = 3kTm

Where, M = Molar mass of the gas

m  = mass of each molecule of gas

R = gas constant 

k = Boltzmann constant

As Temprature is constant

So Vrms   1m

Given : mA>mB>mC

So VrmsA<VrmsB<VrmsC

=> VrmsC>VrmsB>VrmsA

  • 1 answers

Naveen Sharma 8 years, 10 months ago

Ans. Viscosity is an internal property of a fluid that offers resistance to flow.

  • 1 answers

Naveen Sharma 8 years, 10 months ago

Ans. When there are no opposing forces, a moving body tends to keep moving with a steady velocity as we know from Newton's first law of motion. If, however, a resultant force does act on a moving body in the direction of its motion, then it will accelerate per Newton's second law F = ma The work done by the force will become converted into increased kinetic energy in the body. 

Derivation Using Calculus :

Begin with the Work-Energy Theorem : The work that is done on an object is related to the change in its kinetic energy<meta aria-hidden="true" />

 

K = W

Rewrite work as an integral: we can represent the work done in terms of a velocity differential.

K = F. dr

Rewrite force in terms of velocity: mass is a scalar and can therefore be factored out.

 

K = ma.dr

=> K = ma.dr

=> K = mdvdt.dr

=> K = mdrdt.dv

=> K = mv.dv

=> K = 12mv2

 

<meta aria-hidden="true" />

 

  • 1 answers

Naveen Sharma 8 years, 11 months ago

And. It's displacement

  • 2 answers

Naveen Sharma 8 years, 11 months ago

if I started from A and go to B in a direction and then returned back to A and go in a direction opposite to N then my velocity is -ve with respect to N.

Naveen Sharma 8 years, 11 months ago

A vector points in a direction in space. A negative vector (or more precisely "the negative of a vector") simply points the opposite way.

If I drive from my home to my workplace (and then defining my positive direction in that way), then my velocity is positive if I go to work, but negative when I go homefrom work. It is all about direction seen from how I defined my positive axis.

  • 2 answers

Payal Singh 8 years, 11 months ago

Ans. It is due to the internal frictional force that develops between different layers of fluids as they are forced to move relative to each other.

Naveen Sharma 8 years, 11 months ago

The reason behind frictional force between layers of fluids:

i) intermolecular force of cohesion
(ii) molecular momentum exchange

  • 1 answers

Naveen Sharma 8 years, 11 months ago

  1. Stress is defined as a force that can cause a change in an object or a physical body while strain is the change in the form or shape of the object or physical body on which stress is applied.
  2. Stress can occur without strain, but strain cannot occur with the absence of stress.
  3. Stress can be measured and has a unit of measure while strain does not have any unit and, therefore, cannot be measured.
  4. Strain is an object’s response to stress while stress is the force that can cause strain in an object
  • 1 answers

Yakshith K 8 years, 11 months ago

PαT

Therfore, P1T1=P2T2

Substitute the initial and final values and find out the unknown component. 

  • 1 answers

Ankit Kumar 8 years, 11 months ago

generally in physics we all have observed that some values were taken 0 during some derivation and solving numericals.

Actually this step taken by us is the assumption taken by  us to simplify the complex terms whose solution is found to be difficult for even a common person to solve it.

we assume or compare only that angle of contact as 0 that is very very small on comparing with the other quantities which are very large on comparing with the angle. so in some numericals angle of contact is assumed to be zero

  • 1 answers

Bindu Agarwal 8 years, 11 months ago

Two waves (with the same amplitude, frequency, and wavelength) are travelling in opposite directions. Using the principle of superposition, the resulting wave amplitude may be written as:

y ( x , t ) = y m sin ( kx - ωt ) + y m sin ( kx + ωt ) = 2 y m sin ( kx ) cos ( ωt )

This wave is no longer a travelling wave because the position and time dependence have been separated. The the wave amplitude as a function of position is <i>2ym</i>sin(<i>kx</i>). This amplitude does not travel, but stands still and oscillates up and down according to cos(<i>ω t</i>). Characteristic of standing waves are locations with maximum displacement (antinodes) and locations with zero displacement (nodes)..

If two sinusoidal waves having the same frequency (and wavelength) and the same amplitude are travelling in opposite directions in the same medium then, using superposition, the net displacement of the medium is the sum of the two waves.

when the two waves are 180° out-of-phase with each other they cancel, and when they are exactly in-phase with each other they add together. As the two waves pass through each other, the net result alternates between zero and some maximum amplitude. However, this pattern simply oscillates; it does not travel to the right or the left, and thus it is called a "<i>standing wave</i>".

  • 2 answers

Priyanshu Gaur 9 years ago

upper vale ne galat answer deya hai

Naveen Sharma 9 years ago

 

To quantify elasticity, physics defines elasticity as "resistance to change". The greater the resistance to change, the greater is the elasticity of the material and the faster it comes back to its original shape or configuration when the deforming force is removed. By this definition, steel is more elastic than rubber because steel comes back to its original shape faster than rubber when the deforming forces are removed.

  • 1 answers

Bindu Agarwal 9 years ago

(a) Since the spring potential energy is just enough to project the stone 10m highP.E. of stone at 10m height = P.E. of the spring= mgh=(50/1000)*10*10=5J(b) Since 0.5*k*x2 =m*g*(10)  (when x= 3cm)Now 0.5*k*y2 = m*g*(5)y=x/2y=3/2Hence it should be compressed by y cm to throw it to a height of 5m.(c) Since 0.5*k*(0.03)2 = 5k=11111.11

  • 2 answers

Naveen Sharma 9 years ago

Very crudely, centre of mass is the point where the mass appears to be concentrated. In a non-uniform gravitational field, it doesn't coincide with centre of mass. It can also lie outside the body. Since torque can be measured around any axis, it is not necessary for the centre of gravity to lie inside the body.

Shruti Dadhwal 9 years ago

Centre of mass is hypothetical geometry point where whole mass of body is concentrated. It is position vector.Centre of mass may lie outside the body.

  • 2 answers

A NO FORCE BUT GRAVITATIONAL FORCE??????????

B BECAUSE THE DENSITY OF CORK IS LESS THAN WATER . FORCE =GRAVITATIONAL

 

Bindu Agarwal 9 years ago

(a) No force, since it is falling with constant speed.

(b) Here also the gravitational force is balanced by the upward buoyant force. Hence net force is zero.

  • 1 answers

Ankit Kumar 9 years ago

as we know the expresssion for orbital velocity as,

v0= GMR+hwhere v0= orbital velocity  R= radius of sunM=mass of sunR+h= orbital radiusG= gravitational constant

R+h= R0 (Let)

now the above equation can be writtenn as in terms of circumference and time i.e., v0= circumference made by earth / time taken by it.

so, 2π(R+h)t=GMR+has we already as let (R+h)=R0so 2πR0t=GMR0t=2πR0GMR0now when orbital radius is 4 times of orbital radius made by earthi.e., R'0 = 4R0let t' be the time made by unknown planetso t'= 2πR'0GMR'0implies that  t'= 2π4R0GM4R0now tt'=2πR0GMR02π4R0GM4R0on solving the above expression we gett'= 8thence the required time is t'= 8 X 1 years = 8 years

  • 1 answers

Ashwin S 9 years ago

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  • 1 answers

Ashwin S 9 years ago

You can get your doubts cleared instantly, 24/7 with IIT/AIIMS tutors on HashLearn. Download here: http://bit.ly/2fDYZtb

  • 2 answers

Ankit Kumar 8 years, 11 months ago

dear , if cannot explain the answer then please dont suggest any other website

Ashwin S 9 years ago

You can get your doubts cleared instantly, 24/7 with IIT/AIIMS tutors on HashLearn. Download here: http://bit.ly/2fDYZtb

  • 1 answers

Alaikya Tata 9 years, 1 month ago

not necessary that all constant are dimensionless.

for some constant have it has dimension and some dont have

for eg:gravitational constant ,g,planck's constant etc have dimension 

  • 1 answers

Radha Jittu 9 years, 1 month ago

adarsh pls mention height of roof it depends on height if height is 5-9 or something like that then the previous drop would have already touched the ground.

  • 1 answers

Ankit Kumar 9 years ago

A bunch of wire is more flexible than a single one so it will carry more load

  • 1 answers

Ankit Kumar 9 years ago

A combination of core will carry more load

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