Scientific research techniques are used to analyze the effectiveness of political advertising. False True

Economics is the study of how individuals and societies make choices under the condition of

k0ka [10]

Answer:

ig scarcity

Explanation:

Hope it Helps!!!

3 0

2 years ago

Gold forms a substitutional solid solution with silver. Compute the number of gold atoms per cubic centimeter for a silver-gold

evablogger [386]

Answer:

Compute the number of gold atoms per cubic centimeter = 9.052 x 10^21 atoms/cm3

Explanation:

The step by step and appropriate substitution is as shown in the attachment.

From number of moles = Concentration x volume

number of moles = number of particles/ Avogadro's number

Volume = mass/density, the appropriate derivation to get the number of moles of atoms

5 0

3 years ago

Compare both xbox and playstaion. What are pros and cons between the two gaming systems. What is your game system of choice?

fredd [130]

Neither, I would choose a PC because normally with PlayStation and Xbox you have to go to the store to buy more games when on a PC there are some games for free

7 0

2 years ago

Two flat plates, separated by a space of 4 mm, are moving relative to each other at a velocity of 5 m/sec. The space between the

xenn [34]

Answer:

0.008

Explanation:

From the question, the parameters given are:

Velocity V = 5 m/s

Pressure = 10 pa

But pressure = F/A

10 = F/A

F = 10A

Substitute all the parameters into the formula below

Coefficient of viscosity (η) = F × r /[AV]

Where

F = tangential force,

r = distance between layers,

A = Area, and

V = velocity

(η) = 10A × 0.004 /[A × 5]

The A will cancel out

(η) = 10 × 0.004 /[5]

(η) = 0.04 /5

(η) = 0.008

Therefore, the coefficient of viscosity of the fluid is 0.008

5 0

3 years ago

Air at 400kPa, 970 K enters a turbine operating at steady state and exits at 100 kPa, 670 K. Heat transfer from the turbine occu

Sonja [21]

Answer:

a

The rate of work developed is $\frac{\r W}{\r m}= 300kJ/kg$

b

The rate of entropy produced within the turbine is $\frac{\sigma}{\r m}= 0.0861kJ/kg \cdot K$

Explanation:

From the question we are told

The rate at which heat is transferred is $\frac{\r Q}{\r m } = - 30KJ/kg$

the negative sign because the heat is transferred from the turbine

The specific heat capacity of air is $c_p = 1.1KJ/kg \cdot K$

The inlet temperature is $T_1 = 970K$

The outlet temperature is $T_2 = 670K$

The pressure at the inlet of the turbine is $p_1 = 400 kPa$

The pressure at the exist of the turbine is $p_2 = 100kPa$

The temperature at outer surface is $T_s = 315K$

The individual gas constant of air R with a constant value $R = 0.287kJ/kg \cdot K$

The general equation for the turbine operating at steady state is \

$\r Q - \r W + \r m (h_1 - h_2) = 0$

h is the enthalpy of the turbine and it is mathematically represented as

$h = c_p T$

The above equation becomes

$\r Q - \r W + \r m c_p(T_1 - T_2) = 0$

$\frac{\r W}{\r m} = \frac{\r Q}{\r m} + c_p (T_1 -T_2)$

Where $\r Q$ is the heat transfer from the turbine

$\r W$ is the work output from the turbine

$\r m$ is the mass flow rate of air

$\frac{\r W}{\r m}$ is the rate of work developed

Substituting values

$\frac{\r W}{\r m} = (-30)+1.1(970-670)$

$\frac{\r W}{\r m}= 300kJ/kg$

The general balance equation for an entropy rate is represented mathematically as

$\frac{\r Q}{T_s} + \r m (s_1 -s_2) + \sigma = 0$

=> $\frac{\sigma}{\r m} = - \frac{\r Q}{\r m T_s} + (s_1 -s_2)$

generally $(s_1 -s_2) = \Delta s = c_p\ ln[\frac{T_2}{T_1} ] + R \ ln[\frac{v_2}{v_1} ]$

substituting for $(s_1 -s_2)$

$\frac{\sigma}{\r m} = \frac{-\r Q}{\r m} * \frac{1}{T_s} + c_p\ ln[\frac{T_2}{T_1} ] - R \ ln[\frac{p_2}{p_1} ]$

Where $\frac{\sigma}{\r m}$ is the rate of entropy produced within the turbine

substituting values

$\frac{\sigma}{\r m} = - (-30) * \frac{1}{315} + 1.1 * ln\frac{670}{970} - 0.287 * ln [\frac{100kPa}{400kPa} ]$

$\frac{\sigma}{\r m}= 0.0861kJ/kg \cdot K$

5 0

4 years ago