Answer:
(A)0.122 kW (B) Actual cost = 1.056 $/day, Theoretical cost = 0.234 $/day
Explanation:
Solution
Given that:
The coefficient of performance is =3
Heat transfer = 6000kJ/hr
Temperature = 20°C
Cost of electricity = 8 cents per kW-hr
Now
The next step is to find the power input to the refrigerator and compare with the power input considered by a reversed refrigeration cycle operating between reservoirs at the two temperatures.
Thus
(A)The coefficient of performance is given below:
COP = Heat transfer from freezer/Power input
3 =6000/P
P =6000/3
P= 2000
P = 2000 kJ/hr = 2000/(60*60) kW
= 2000 (3600)kW
= 0.55 kW
Thus
The ideal coefficient of performance = T_low/(T_high - T_low)
= (0+273)/(20-0)
= 13.65
So,
P ideal = 6000/13.65 = 439.6 kJ/hr
= 439.6/(60*60) kW
= 0.122 kW
(B)For the actual cost we have the following:
Actual cost = 0.55 kW* 0.08 $/kW-hr = $ 0.044 per hour
= 0.044*24 $/day
= 1.056 $/day
For the theoretical cost we have the following:
Theoretical cost = 0.122 kW* 0.08 $/kW-hr = $ 0.00976 per hour
= 0.00976*24 $/day
= 0.234 $/day
Answer:
Go through the solution attached. It is very detailed.
Explanation:
The sample of 81 students was selected with a mean score of 90, this illustrates an example of a right tailed one sample z test.
<h3>How to illustrate the sample?</h3>
From the information given, the teacher claims that the mean score of students in his class is greater than 82 with a standard deviation of 20. In this case, the right tailed one sample z test is used.
The z value will be:
= (90 - 82)/20/✓81
= 3.6
Since 3.6 > 1.645, the null hypothesis will be rejected as there's enough evidence to support the teacher's claim.
When an online medicine shop claims that the mean delivery time for medicines is less than 120 minutes with a standard deviation of 30 minutes, the left tailed one sample test is used.
The z value will be:
= (100 - 120)/(30/✓49)
= -4.66
The null hypothesis is rejected as there is enough evidence to support the claim of the medicine shop.
Learn more about sampling on:
brainly.com/question/17831271
#SPJ1
Answer:
too big, too small, deadlines, not enough materials
Explanation:
Answer:
Carbon dioxide have higher temperature at the final stage.
Explanation:
Given that
We know that
γ=1.28 for carbon dioxide
γ=1.4 for air
For isentropic expansion
Now for carbon dioxide γ=1.28
Now for air γ=1.4
So carbon dioxide have higher temperature at the final stage.