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V125BC [204]
3 years ago
10

Determine the speed of sound in air at 400 K. Also determine the Mach number of an aircraft moving in the air at a velocity of 3

10 m/s.
The gas constant of air is R = 0.287 kJ/kg*K. Its specific heat ratio at room temperature is k = 1.4.
Engineering
1 answer:
Reika [66]3 years ago
7 0

Answer:

\alpha = \sqrt{1.4 *0.287 \frac{KJ}{Kg K}*\frac{1000J}{1KJ} *400 K}= 400.899 m/s

Ma= \frac{310 m/s}{400.899 m/s}= 0.773

Explanation:

For this case we have given the following data:

T= 400 K represent the temperature for the air

v = 310 m/s represent the velocity of the air

k = 1.4 represent the specific heat ratio at the room

R = 0.287 KJ/ Kg K represent the gas constant  for the air

And we want to find the velocity of the air under these conditions.

We can calculate the spped of the sound with the Newton-Laplace Equation given by this equation:

\alpha = \sqrt{\frac{K}{\rho}}=\sqrt{k RT}

Where K = is the Bulk Modulus of air, k is the adiabatic index of air= 1.4, R = the gas constant  for the air, \rho the density of the air and T the temperature in K

So on this case we can replace and we got:

\alpha = \sqrt{1.4 *0.287 \frac{KJ}{Kg K}*\frac{1000J}{1KJ} *400 K}= 400.899 m/s

The Mach number by definition is "a dimensionless quantity representing the ratio of flow velocity past a boundary to the local speed of sound" and is defined as:

Ma=\frac{v}{\alpha}

Where v is the flow velocity and \alpha the volocity of the sound in the medium and if we replace we got:

Ma= \frac{310 m/s}{400.899 m/s}= 0.773

And since the Ma<0.8 we can classify the regime as subsonic.

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*6–24. The beam is used to support a dead load of 400 lb&gt;ft, a live load of 2 k&gt;ft, and a concentrated live load of 8 k. D
lisabon 2012 [21]

Answer:

(a) maximum positive reaction at A = 64.0 k

(b) maximum positive shear at A = 32.0 k

(c) maximum negative moment at C = -540 k·ft

Explanation:

Given;

dead load  Gk = 400 lb/ft

live load Qk = 2 k/ft

concentrated live load Pk =8 k

(a) from the influence line for vertical reaction at A, the maximum positive reaction is

A_{ymax} = 2*(8) +(1/2(20 - 0)* (2))*(2 + 0.4) = 64 k

See attachment for the calculations of (b) & (c) including the influence line

3 0
3 years ago
Find the differential and evaluate for the given x and dx: y=sin2xx,x=π,dx=0.25
Sedaia [141]

By applying the concepts of differential and derivative, the differential for y = (1/x) · sin 2x and evaluated at x = π and dx = 0.25 is equal to 1/2π.

<h3>How to determine the differential of a one-variable function</h3>

Differentials represent the <em>instantaneous</em> change of a variable. As the given function has only one variable, the differential can be found by using <em>ordinary</em> derivatives. It follows:

dy = y'(x) · dx     (1)

If we know that y = (1/x) · sin 2x, x = π and dx = 0.25, then the differential to be evaluated is:

y' = -\frac{1}{x^{2}}\cdot \sin 2x + \frac{2}{x}\cdot \cos 2x

y' = \frac{2\cdot x \cdot \cos 2x - \sin 2x}{x^{2}}

dy = \left(\frac{2\cdot x \cdot \cos 2x - \sin 2x}{x^{2}} \right)\cdot dx

dy = \left(\frac{2\pi \cdot \cos 2\pi -\sin 2\pi}{\pi^{2}} \right)\cdot (0.25)

dy = \frac{1}{2\pi}

By applying the concepts of differential and derivative, the differential for y = (1/x) · sin 2x and evaluated at x = π and dx = 0.25 is equal to 1/2π.

To learn more on differentials: brainly.com/question/24062595

#SPJ1

4 0
2 years ago
A construction manager is looking for workers to build a series of walkways within a large garden apartment. What type of workme
Lesechka [4]

Answer:

<u>construction workers</u>

Explanation:

A construction worker is usually someone with the technical skills and abilities needed to manually construct physical infrastructures.

Since a walkway is an infrastructure, hiring skilled construction workers should perform the project of building the series of walkways within the large garden apartment.

3 0
3 years ago
. In one stroke of a reciprocating compressor, helium is isothermally and reversibly compressed in a piston + cylinder from 298
andriy [413]

Answer:

5.7058kj/mole

Explanation:

Please see attachment for step by step guide

5 0
3 years ago
What is the IMA of this pulley belt system if the diameter of the input
Stella [2.4K]

Answer:

2.8

Explanation:

The ideal mechanical advantage of the pulley IMA  = D'/D where D' = diameter of output pulley = 7 inches and D = diameter of input pulley = 2.5 inches

So, IMA = D'/D

= 7/2.5

= 2.8

So, the ideal mechanical advantage of the pulley IMA = 2.8

8 0
2 years ago
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