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3 years ago

7

Which statements describe the motion of car A and car B? Check all that apply. Car A and car B are both moving toward the origin

. Car A and car B are moving in opposite directions. Car A is moving faster than car B. Car A and car B started at the same location. Car A and car B are moving toward each other until they cross over.

1 answer:

vekshin13 years ago

8 0

Answer:

car a is moving faster than the car b

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A colorful design for a product meant to appeal to a preschool audience reflects which of the following points in industrial des

lord [1]

Appeal to emotion

the product doesn’t need to be colorful to function but it would be more appealing to the intended audience if it was

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2 years ago

A 1.00 liter solution contains 0.46 M hydrocyanic acid and 0.35 M potassium cyanide If 25.0 mL of water are added to this system

victus00 [196]

I won leader solution contain 0.46 mL of hydronic I said of 0.3 potassium

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2 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

3 years ago

How are industries related to systems

REY [17]

Answer:

The industrial systems of the future are seen as complex systems, composed of vast numbers of devices, interacting with each other and with enterprise systems continuously.

summary:

they are related because they ARE a system. well, a type.

hope this helps!! :)

7 0

2 years ago

zener shunt regulator employs a 9.1-V zener diode for which VZ = 9.1 V at IZ = 9 mA, with rz = 40 and IZK= 0.5 mA. The available

gulaghasi [49]

Answer:

$V_z=9.1v$

$V_{zo}=8.74V$

$I=10mA$

$R=589 ohms$

Explanation:

From the question we are told that:

Zener diode Voltage $V_z=9.1-V$

Zener diode Current $I_z=9 .A$

Note

$rz = 40\\\\IZK= 0.5 mA$

Supply Voltage $V_s=15$

Reduction Percentage $P_r= 50 \%$

Generally the equation for Kirchhoff's Voltage Law is mathematically given by

$V_z=V_{zo}+I_zr_z$

$9.1=V_{z0}+9*10^{-3}(40)$

$V_{zo}=8.74V$

Therefore

$At I_z-10mA$

$V_z=V_{z0}+I_zr_z$

$V_z=8.74+(10*10^{-3}) (40)$

$V_z=9.1v$

Generally the equation for Kirchhoff's Current Law is mathematically given by

$-I+I_z+I_l=0$

$I=10mA+\frac{V_z}{R_l}$

$I=10mA+\frac{9.1}{0}$

$I=10mA$

Therefore

$R=\frac{15V-V_z}{I}$

$R=\frac{15-9.1}{10*10^{-3}}$

$R=589 ohms$

5 0

3 years ago