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lilavasa [31]
3 years ago
12

A 900 kg car is accelerated from a speed of 10 m/s to 30 m/s. An estimated heat loss of 20 BTU's occurs during the acceleration.

Also, the car increases its elevation by 20m and the internal energy increases by 0.1 kJ/kg. Determine the amount of work that must be done to the system in kJ.
Engineering
1 answer:
Strike441 [17]3 years ago
4 0

Answer:

Work = 651,1011 kJ

Explanation:

Let´s take the car as a system in order to apply the first law of thermodynamics as follows:

E_{in}- E_{out}=E_{system,final}- E_{system,initial}

Where

E_{in}- E_{out}=(Q_{in}-Q_{out})_{heat}+(W_{in}-W_{out})_{work}+(Em_{in}-Em_{out})_{mass}

And considering that there is no mass transfer and that the only energy flows that interact with the system are the heat losses and the work needed to move the car we have:

E_{in}- E_{out}=-Q_{out}+W_{in}

Regarding the energy system we have the following:

E_{system,final}- E_{system,initial}=(U_{f}-U_{i})_{internal}+(1/2m(V^2_{f}-V^2_{i}))_{kinetic}+(mg(h_{f}-h_{i}))_{potential}

By doing the calculations we have:

E_{system,final}- E_{system,initial}=[0,1*900]_{internal}+[0,5*900(30^2-10^2)/1000)_{kinetic}+(900*10*(20-0)/1000)_{potential}\\E_{system,final}- E_{system,initial}=90+360+180=630kJ

Consider that in the previous calculation, the kinetic and potential energy terms were divided by 1.000 to change the units from J to kJ.

Finally, the work needed to move the car under the required conditions is calculated as follows:

W_{in}=Q_{out}+E_{system,final}- E_{system,initial}\\W_{in}=21,1011+630=651,1011kJ

Consider that in the previous calculation, the heat loss was changed previously from BTU to kJ.

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Answer:

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Danny enjoys studying transportation networks and systems. Which field of engineering should he pursue?
andre [41]

Answer:

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Explanation:

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<u>Civil engineering is regarded as the second--oldest form of engineering studies in the field of engineering.</u>

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8 0
3 years ago
The product second moment of area Ixy is found by multiplying Ix and Iy. a)True b)- False
Kamila [148]

Answer:

(b)False

Explanation:

I_{xy} defined as

      I_{xy} =\int \left (x\cdot y\right )dA

Where x is the distance from centroidal x-axis

           y is the distance from centroidal y-axis

          dA is the elemental area.

The product of x and y can be positive or negative ,so the value of  I_{xy} can be positive as well as negative .

So from the above expressions we can say that the product of I_{x},I_y is different from I_{xy} .

7 0
4 years ago
List principles that are most relevant to drop jump exercise and justify your answers that selected principles you
ycow [4]

The principles referred to in the question are called biomechanical principles. Some of them are:

  • Principles of Force; and
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<h3>What principle is most relevant to jumping?</h3>


The principle that is most relevant to jumping is called Angular Momentum.

<h3>What is Angular Momentum?</h3>

Simply defined, this refers to the velocity of the rotation of a body around an axis or a fixed point.

Other principles of biomechanics are the principles of:

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See more about biomechanical principles at:
brainly.com/question/1087668

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2 years ago
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Zolol [24]

Answer:

(C) ln [Bi]

Explanation:

Radioactive materials will usually decay based on their specific half lives. In radioactivity, the plot of the natural logarithm of the original radioactive material against time will give a straight-line curve. This is mostly used to estimate the decay constant that is equivalent to the negative of the slope. Thus, the answer is option C.

3 0
3 years ago
Read 2 more answers
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