1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
aliina [53]
3 years ago
8

A closed, rigid tank fitted with a paddle wheel contains 2.0 kg of air, initially at 200oC, 1 bar. During an interval of 10 minu

tes, the paddle wheel transfers energy to the air at a rate of 1 kW. During this time interval, the air also receives energy by heat transfer at a rate of 0.5 kW. These are the only energy transfers. Assume the ideal gas model for the air, and no overall changes in kinetic or potential energy. Do not assume specific heats are constant. Determine the change in specific internal energy for the air, in kJ/kg, and the final temperature of the air, in oC.
Engineering
1 answer:
RUDIKE [14]3 years ago
8 0

Answer:

T=833.8 °C

Explanation:

Given that

m= 2 kg

T₁=200 °C

time ,t= 10 min = 600 s

Work input = 1 KW

Work input = 1 x 600 KJ=600 KJ

Heat input = 0.5 KW

Q= 05 x 600 = 300 KJ

Gas is ideal gas.

We know that for ideal gas internal energy change given as

ΔU= m Cv ΔT

For air Cv= 0.71 KJ/kgK

From first law of thermodynamics

Q  = ΔU +W

Heat input taken as positive and work in put taken as negative.

300 KJ = - 600 KJ + ΔU

ΔU = 900 KJ

ΔU= m Cv ΔT

900 KJ = 2 x 0.71 x (T- 200 )

T=833.8 °C

So the final temperature is T=833.8 °C

You might be interested in
A spherical gas container made of steel has a(n) 17-ft outer diameter and a wall thickness of 0.375 in. Knowing that the interna
Arte-miy333 [17]

Answer:

Maximum Normal Stress σ = 8.16 Ksi

Maximum Shearing Stress τ = 4.08 Ksi

Explanation:

Outer diameter of spherical container D = 17 ft

Convert feet to inches D = 17 x 12 in = 204 inches

Wall thickness t = 0.375 in

Internal Pressure P = 60 Psi

Maximum Normal Stress σ = PD / 4t

σ = PD / 4t

σ = (60 psi x 204 in) / (4 x 0.375 in)

σ = 12,240 / 1.5

σ = 8,160 P/in

σ = 8.16 Ksi

Maximum Shearing Stress τ = PD / 8t

τ = PD / 8t

τ = (60 psi x 204 in) / (8 x 0.375 in)

τ = 12,240 / 3

τ = 4,080 P/in

τ = 4.08 Ksi

7 0
3 years ago
soccer is also called association football" A soccer ball is a sphere, with circumference of 70 centimeters. in developing a new
timama [110]

Answer: Weight on Mars = 0.02593N

Explanation:

Given; Circumference C of Sphere = 70cm = 0.7m,

Specific Gravity S. G. of material = 1.21,

acceleration due to gravity in the Mars gm = 3.7m/s^2

We know that Weight W = mass m × acceleration due to gravity.

Let the Weight in on the Mars be Wm.

Wm = m × gm

Since we are given gm, we need to calculate for m. (Note that mass m is the same everywhere)

But mass = specific gravity × volume

Since we know the specific gravity, let's go ahead to calculate for the volume of the ball.

We know that Volume of a Sphere V = (4/3)πr^3

To get r, we know that C = 2πr

Therefore, r = C/(2π) = 0.7/(2π) = (7/10)/2π = 7/20π (in meters)

V = (4/3)*π×(7/20π)^3 = 343/6000π^2 (in meter^3)

m = 343/6000π^2 × 1.21 = 7.01×10^(-3)kg

Wm = 7.01×10^(-3) × 3.7 = 0.02593N

8 0
3 years ago
The water in a 25-m-deep reservoir is kept inside by a 140-m-wide wall whose cross section is an equilateral triangle as shown i
koban [17]

Answer:  (a) 9.00 Mega Newtons or 9.00 * 10^6 N

               (b)  17.1 m

Explanation:  The length of wall under the surface can be given by

                                            b=25m/sin(60)\\=28.867

The average pressure on the surface of the wall is the pressure at the centeroid of the equilateral triangular block which can be then be calculated by multiplying it with the Plate Area which will provide us with the Resultant force.

F(resultant) = Pavg ( A) = (Patm +  \rho g h c)*A \\= [100000 N/m^2 + (1000 kg/m^3 * 9.81 m/s^2 * 25m/2)]* (140*25m/sin60)\\= 8.997*10^8 N \\= 9.0*10^8 N

Noting from the Bernoulli  equation that

Po/\rho g sin60 = 100000/1000 * 9.81* sin(60) = 11.77 m \\ \\

From the second image attached the distance of the pressure center from the free surface of the water along the surface of the wall is given by:

Yp = s+\frac{b}{2} +\frac{b^2}{s+\frac{b}{2}+Po/\rho g sin60}= 0+\frac{28.87}{2} +\frac{28.87^2}{0+\frac{28.87}{2}+100000 /1000 *9.81 sin60} = 17.1 m

Substituting the values gives us the the distance of the surface to be equal to = 17.1 m

7 0
3 years ago
__________ use cleaning solutions that eventually become spent and must be disposed of properly
ohaa [14]

Answer:Part washers

Explanation:

I did it..

4 0
3 years ago
A tubular reactor has been sized to obtain 98% conversion and to process 0.03 m^3/s. The reaction is a first-order irreversible
Zolol [24]

Answer:

The conversion in the real reactor is = 88%

Explanation:

conversion = 98% = 0.98

process rate = 0.03 m^3/s

length of reactor = 3 m

cross sectional area of reactor = 25 dm^2

pulse tracer test results on the reactor :

mean residence time ( tm) = 10 s and variance (∝2) = 65 s^2

note:  space time (t) =

t = \frac{A*L}{Vo}   Vo = flow metric flow rate , L = length of reactor , A = cross sectional area of the reactor

therefore (t) = \frac{25*3*10^{-2} }{0.03} = 25 s

since the reaction is in first order

X = 1 - e^{-kt}

e^{-kt} = 1 - X

kt = In \frac{1}{1-X}

k = In \frac{1}{1-X} / t  

X = 98% = 0.98 (conversion in PFR ) insert the value into the above equation then  

K = 0.156 s^{-1}

Calculating Da for a closed vessel

; Da = tk

      = 25 * 0.156 = 3.9

calculate Peclet number Per using this equation

0.65 = \frac{2}{Per} - \frac{2}{Per^2} ( 1 - e^{-per})

therefore

\frac{2}{Per} - \frac{2}{Per^2} (1 - e^{-per}) - 0.65 = 0

solving the Non-linear equation above( Per = 1.5 )

Attached is the Remaining part of the solution

3 0
3 years ago
Other questions:
  • What is the perimeter of 14-7 and 3-4
    9·1 answer
  • Global Courier Services will ship your package based on how much it weighs and how far you are sending the package. Packages abo
    14·1 answer
  • Write a program to input 6 numbers. After each number is input, print the biggest of the numbers entered so far.
    12·1 answer
  • The minimum requirements for engineering documents are enumerated in
    10·1 answer
  • A wood pole with a diameter of 10 in. has a moisture content of 5%. The fiber saturation point (FSP) for this wood is 30%. The w
    9·1 answer
  • Cómo se llama el componente, que permite abrir o cerrar un circuito eléctrico
    8·1 answer
  • A wire is 0.92 m long and 1.2 mm2 in cross-sectional area. It carries a current of 5.0 A when a 2.2 V potential difference is ap
    6·1 answer
  • 2.
    14·1 answer
  • 28. What is the value of a resistor in a series circuit if you measure 0.5 amps flowing through it and 15 volts
    10·1 answer
  • When bending metal, the material on the outside of the curve stretches while the material on the inside of the curve compresses.
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!