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
saw5 [17]
2 years ago
10

The rate at which heat enters an air conditioned building is often roughly proportional to the difference in temperature between

inside and outside.
(a) Under this assumption, show that the cost of operating an air con- ditioner is proportional to the square of the temperature difference.
(b) Give a numerical example for a typical house and discuss implications for your electric bill.
(c) Suppose instead that heat enters the building at a rate proportional to the square-root of the temperature difference between inside and outside. How would the operating cost now depend on the temperature difference?
Physics
1 answer:
erma4kov [3.2K]2 years ago
4 0

Answer:

Considering first question

    Generally the coefficient of performance of the air condition  is mathematically represented as

   COP  =  \frac{T_i}{T_o - T_i}

Here T_i is the inside temperature

while  T_o is the outside temperature

What this coefficient of performance represent is the amount of heat the air condition can remove with 1 unit of electricity

So it implies that the air condition removes   \frac{T_i}{T_o - T_i} heat with 1 unit of electricity

Now from the question we are told that the rate at which heat enters an air conditioned building is often roughly proportional to the difference in temperature between inside and outside. This can be mathematically represented as

         Q \ \alpha \ (T_o - T_i)

=>        Q= k (T_o - T_i)

Here k is the constant of proportionality

So  

    since  1 unit of electricity  removes   \frac{T_i}{T_o - T_i}  amount of heat

   E  unit of electricity will remove  Q= k (T_o - T_i)

So

      E =  \frac{k(T_o - T_i)}{\frac{T_i}{ T_h - T_i} }

=>   E = \frac{k}{T_i} (T_o - T_i)^2

given that  \frac{k}{T_i} is constant

    =>  E \  \alpha  \  (T_o - T_i)^2

From this above equation we see that the  electricity required(cost of powering and operating the air conditioner) is approximately proportional to the square of the temperature difference.

 Considering the  second question

Assuming that  T_i   =  30 ^oC

 and      T_o  =  40 ^oC

Hence  

     E = K (T_o - T_i)^2

Here K stand for a constant

So  

        E = K (40 -  30)^2

=>      E = 100K

Now if  the  T_i   =  20 ^oC

Then

       E = K (40 -  20)^2

=>      E = 400 \ K

So  from this see that the electricity require (cost of powering and operating the air conditioner)when the inside temperature is low  is  much higher than the electricity required when the inside temperature is higher

Considering the  third question

Now in the case where the  heat that enters the building is at a rate proportional to the square-root of the temperature difference between inside and outside

We have that

       Q = k (T_o - T_i )^{\frac{1}{2} }

So

       E =  \frac{k (T_o - T_i )^{\frac{1}{2} }}{\frac{T_i}{T_o - T_i} }

=>   E =  \frac{k}{T_i} * (T_o - T_i) ^{\frac{3}{2} }

Assuming \frac{k}{T_i} is a constant

Then  

     E \ \alpha \ (T_o - T_i)^{\frac{3}{2} }

From this above equation we see that the  electricity required(cost of powering and operating the air conditioner) is approximately proportional to the square root  of the cube of the  temperature difference.

   

You might be interested in
Two common ions of manganese are Mn2+ and Mn3+. Which binary ionic compound is likely to form? A) Mn2N3 B) MnBr4 C) MnCl D) MnO
meriva
Given that Oxygen has an oxidation state of  2 -, you can combine Mn 3+ with O 2- ions to form Mn2O3, and you can combine Mn 2+ with O 2- to form Mn2O2 which is MnO.

The other compounds imply oxidation states of N, Br and Cl that does not exist.

Therefore, the answer is the option D. MnO
4 0
3 years ago
Read 2 more answers
in a lever, a load of 600N is lifted by using 400 effort. If the load is at the distance of 20cm and the effort at the distance
koban [17]

Explanation:

Load (l) = 680N

Effort (E) = 500N

Length slope (l) = 12m

Height slope (h) = 8 m

Output = load * height

680 *8 = 5.44 *103 J

The Input = effort * length = 500 *12 = 6000J

the Mechanical advantage (M.A) = load effort= 600500=1.36

the Velocity ratio (V.R) =lh=128 = 1.5

the Efficiency =M.A100%V.R= 90.6%

8 0
2 years ago
24. While measuring the length of a book, the reading of the scale at one end is 5.0 cm and at the other end is 20.5
il63 [147K]

Answer:

...do

Explanation:

24. While measuring the length of a book, the reading of the scale at one end is 5.0 cm and at the other end is 20.5

cm. What is the length of the book in mm?

25. Explain the modifications

3 0
3 years ago
Friction, conduction and induction are three ways of creating a static charge on an object. Which method or methods will produce
Agata [3.3K]
Friction as it will move charge (electrons) from one object to another
5 0
3 years ago
What are some ways to improve heat islands temperature
Vera_Pavlovna [14]

Answer:

1. Increase shade around your home. Planting trees and other vegetation

2.lowers surface and air temperatures by providing shade and cooling through evapotranspiration.  

3.Install green roofs.  

4.Install cool roofs.  

5.Use energy-efficient appliances and equipment.  

6.Check on your friends, family, and neighbors.

Explanation:

3 0
2 years ago
Other questions:
  • !!!!!<br> Is blood an incompressible fluid or a compressible fluid?
    12·2 answers
  • Young people do have the ability to initiate a positive change in their community. Depending where they live they could always g
    7·2 answers
  • A magnet contains a ____ numbers of magnetic domains
    10·2 answers
  • A metal wire of resistance R is cut into two pieces of equal length. The two pieces are connected together side by side. Part A
    11·1 answer
  • The actuon of a lever is affected by the?
    8·1 answer
  • If a truck loses 5610 J of energy as it slows down due to an external force of 425 N, what distance will it have moved after the
    6·1 answer
  • A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 10.0 min
    13·1 answer
  • I need help with one through six please
    6·1 answer
  • How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?.
    12·1 answer
  • What is inertia?by Walter Levin..<br>​
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!