For a 20 ohm resistor R, the current i = 2 A. What is the voltage V? Submit your answer as a number without units.

Problem 4.079 SI A rigid tank whose volume is 3 m3, initially containing air at 1 bar, 295 K, is connected by a valve to a large

salantis [7]

Answer:

$Q_{cv} = -1007.86kJ$

Explanation:

Our values are,

State 1

$V=3m^3\\P_1=1bar\\T_1 = 295K$

We know moreover for the tables A-15 that

$u_1 = 210.49kJ/kg\\h_i = 295.17kJkg$

State 2

$P_2 =6bar\\T_2 = 296K\\T_f = 320K$

For tables we know at T=320K

$u_2 = 228.42kJ/kg$

We need to use the ideal gas equation to estimate the mass, so

$m_1 = \frac{p_1V}{RT_1}$

$m_1 = \frac{1bar*100kPa/1bar(3m^3)}{0.287kJ/kg.K(295k)}$

$m_1 = 3.54kg$

Using now for the final mass:

$m_2 = \frac{p_2V}{RT_2}$

$m_2 = \frac{1bar*100kPa/6bar(3m^3)}{0.287kJ/kg.K(320k)}$

$m_2 = 19.59kg$

We only need to apply a energy balance equation:

$Q_{cv}+m_ih_i = m_2u_2-m_1u_1$

$Q_{cv}=m_2u_2-m1_u_1-(m_2-m_1)h_i$

$Q_{cv} = (19.59)(228.42)-(3.54)(210.49)-(19.59-3.54)(295.17)$

$Q_{cv} = -1007.86kJ$

The negative value indidicates heat ransfer from the system

7 0

3 years ago

2)Prueba de presión Cuando a una persona se le somete a una prueba de presión, por lo general se le indica que, al llegar el rit

Olin [163]

Usando la ecuación de regresión que modela la frecuencia cardíaca máxima, podemos obtener el valor predicho de los problemas dados así:

La ecuación lineal que modela la frecuencia cardíaca máxima permitida en función de la edad del paciente está relacionada con la fórmula:

m = - 0,875x + 190

<em>x = edad del paciente; m = máx. frecuencia cardíaca permitida</em>

1.) <u>Frecuencia cardíaca máxima permitida para una persona de 50 años:</u>

Sustituye x = 50 en la ecuación:

m = -0,875 (50) + 190

m = 146,25

Por lo tanto, la frecuencia cardíaca máxima permitida es de aproximadamente 146 latidos / min.

2.) <u>Edad para una persona con frecuencia cardíaca máxima de 160 latidos / min</u>:

Sustituye m = 160 en la ecuación:

160 = -0,875x + 190

0,875x = 190 - 160

0,875x = 30

x = 30 / 0,875

x = 34,28

Por tanto, la edad de la persona sería de unos 34 años.

Más información: brainly.com/question/25395533

3 0

2 years ago

A homogeneous 800kg bar AB is supported at either end by a cable asshown in the figure

aleksandr82 [10.1K]

The smallest area of each cable if the stress is not to exceed 90MPa in bronze is 43.6 mm² and 120MPa in steel is 32.7 mm².

<h3>What is normal stress?</h3>

If the direction of deformation force is perpendicular to the cross-sectional area of the body, the stress is called normal stress. Changes in wire length and body volume will be normal.

σ = P/A

Where, σ = Normal stress

P = Pressure

A = Area

1 Kg = 9.81 N

800 kg = 7848 N

Since the rod is half bronze and half steel

800 kg = 7848/2

= 3924 N

Pₙ = Fₙ = 3924 N [n = Bronze]

Pₓ = 3924 N [x = steel]

Given,

σₙ = 90MPa

σₓ = 120MPa

Aₙ = ?

Aₓ = ?

Aₙ = Pₙ/σₙ

Aₙ = 3924/90

Aₙ = 43.6 mm²

Aₓ = Pₓ/σₓ

Aₓ = 3924/120

Aₓ = 32.7 mm²

To know more about normal stress, visit:

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#SPJ9

4 0

1 year ago

if this light stays on after the initial startup of the vehicle it signals a warning that there is something wrong with the serv

NemiM [27]

Service brake system indicator is the warning that there is something wrong with the service brake system. Hence option f is correct.

<h3>What is indicator?</h3>

Amber-colored indicator lights can be found at the front, back, and occasionally on the left and right sides of the vehicle. Whether you're turning left, right, or into oncoming traffic, you use your indicators to signal your planned change of direction.

When this light turns on, one of two things will happen. Either the parking brake is engaged or the hydraulic fluid (brake fluid) in the master cylinder is low. Your brakes are made up of a system of hydraulic oil-filled tubes called brake lines.

Thus, service brake system indicator is the warning that there is something wrong with the service brake system. Hence option f is correct.

To learn more about indicator, refer to the link below:

brainly.com/question/28093573

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7 0

11 months ago

When brazing, the lowest effective brazing temperatures possible should be used to minimize the effects of heat on the base meta

nordsb [41]

Answer:

False

Explanation:

5 0

2 years ago

For a 20 ohm resistor R, the current i = 2 A. What is the voltage V? Submit your answer as a number without units. ​

For a 20 ohm resistor R, the current i = 2 A. What is the voltage V? Submit your answer as a number without units.