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3 years ago

For flow over a flat plate with an extremely rough surface, convection heat transfer effects are known to be correlated by the

Engineering

1 answer:

Greeley [361]3 years ago

8 0

Answer: the surface shear stress at x =1m from the leading edge of the plate is 4.1973 N/m²

Explanation:

Given that;

density s = 1.16 kg/m³

velocity = u = 50 m/s

kinetic viscosity r = 15.89 × 10⁻⁶ m²/s

xL = 1m from the leading edge of the plate

Now Reynold number (Rex)

Rex = UxL / r

Rex = (50 m/s × 1m ) / 15.89 × 10⁻⁶ m²/s

Rex = 3146633.1025

since Rex is greater than 5×10⁵ { Turbulent flow }

so Local skin friction coefficient

⇒ Cfx = 0.0577 / (Rex)^1/5

Cfx = 0.0577 / (3146633.1025)^1/5

Cfx = 0.0028947

Now Shear stress (y)

y = Cfx × 1/2 × su²

y = 0.0028947 × 1/2 × 1.16 × (50)²

y = 4.1973 N/m²

∴ the surface shear stress at x =1m from the leading edge of the plate is 4.1973 N/m²

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What is the purpose of having a ventilation system on board a motorized vessel?.

chubhunter [2.5K]

The purpose of having a ventilation system on board a motorized vessel is : To remove flammable gas from a vessel to avoid explosions.

<h3>Meaning of ventilation system</h3>

A ventilation system can be defined as a system that allows for removal of gases from a vessel to the atmosphere.

A Ventilation system is very important in every motorized vessel because they help to eliminate or remove flammable gases that are dangerous and are liable to explode when held in a large amount in the engine.

In conclusion, The purpose of having a ventilation system on board a motorized vessel is to remove flammable gas from a vessel their by avoiding explosions.

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2 years ago

Two sites are being considered for wind power generation. On the first site, the wind blows steadily at 7 m/s for 3000 hours per

kirill [66]

Solution :

Given :

$V_1 = 7 \ m/s$

Operation time, $T_1$ = 3000 hours per year

$V_2 = 10 \ m/s$

Operation time, $T_2$ = 2000 hours per year

The density, ρ = $1.25 \ kg/m^3$

The wind blows steadily. So, the K.E. = $(0.5 \dot{m} V^2)$

$= \dot{m} \times 0.5 V^2$

The power generation is the time rate of the kinetic energy which can be calculated as follows:

Power = $\Delta \ \dot{K.E.} = \dot{m} \frac{V^2}{2}$

Regarding that $\dot m \propto V$ . Then,

Power $\propto V^3$ → Power = constant x $V^3$

Since, $\rho_a$ is constant for both the sites and the area is the same as same winf turbine is used.

For the first site,

Power, $P_1= \text{const.} \times V_1^3$

$P_1 = \text{const.} \times 343 \ W$

For the second site,

Power, $P_2 = \text{const.} \times V_2^3 \ W$

$P_2 = \text{const.} \times 1000 \ W$

5 0

3 years ago

For a body moving with simple harmonic motion state the equations to represent: i) Velocity ii) Acceleration iii) Periodic Time

max2010maxim [7]

Answer with Explanation:

The general equation of simple harmonic motion is

$x(t)=Asin(\omega t+\phi)$

where,

A is the amplitude of motion

$\omega$ is the angular frequency of the motion

$\phi$ is known as initial phase

part 1)

Now by definition of velocity we have

$v=\frac{dx}{dt}\\\\\therefore v(t)=\frac{d}{dt}(Asin(\omega t+\phi )\\\\v(t)=A\omega cos(\omega t+\phi )$

part 2)

Now by definition of acceleration we have

$a=\frac{dv}{dt}\\\\\therefore a(t)=\frac{d}{dt}(A\omega cos(\omega t+\phi )\\\\a(t)=-A\omega ^{2}sin(\omega t+\phi )$

part 3)

The angular frequency is related to Time period 'T' as $T =\frac{2\pi }{\omega }$

where

$\omega$ is the angular frequency of the motion of the particle.

Part 4) The acceleration and velocities are plotted below

since the maximum value that the sin(x) and cos(x) can achieve in their respective domains equals 1 thus the maximum value of acceleration and velocity is $A\omega ^{2}$ and $A\omega$ respectively.

4 0

3 years ago

True or False: Stress can effectively be relieved through physical activity, getting enough rest and sleep, and relaxation techn

Neko [114]

Answer:

True

Explanation:

Actually this are some of the nitty gritty answers and ways to control or stip stress, lemme explain them you see stress most of the time may come from deep thoughts that are and are pushing you to the wall, and you in your state you as you react to that which is so demanding as it makes you tense,so if at you will incorporate physical activities like running, jogging or push ups the psychological tension in you is broken as you focus so much on the activities rather than the tension, then getting enough rest cools the mind and all your thoughts settle as in your brain starts to adapt to chilling and relaxation and enough sleep will actually make ones head to be at peace because if you lack enough sleep you might have an excruciating migraine when you are stressed up and finally relaxation techniques makes the body accept the situation and then you manouver out of it as you grow strongly.

Hope this will help!

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3 years ago

Read 2 more answers

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kondaur [170]

Answer:

“height is a quantitative variable ”

Explanation:

According to the question asked, answer is “height is a quantitative variable ”

Height is a quantitative variable because it is related to the measurement and in measurement, when we measure something we deal with number (numerical data)

Numerical data is a type of quantitative data that is why we say “height is a quantitative variable”

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3 years ago