A heat pump receives heat from a lake that has an average winter time temperature of 6o C and supplies heat into a house having an average temperature of 25o C. (a) If the house loses heat to the atmosphere at the rate of 60,000 kJ/h, determine the minimum power supplied to the heat pump (in kW) that can maintain the interior temperature of the house at 25o C. (b) Suppose the heat pump absorbs energy from the ground (10o C) instead of the lake, Calculate the minimum power (in kW) required for the heat pump.

Answers

Answer 1

Answer:

Explanation:

60000 kJ / h = 60000 x 1000 / (60 x 60 )

= 16667 J /s

a)

[tex]\frac{Q_H}{W} =\frac{T_H}{T_H-T_C}[/tex]

where [tex]Q_H[/tex] and [tex]W[/tex] are heat supplied and heat given from  outside source .

Here [tex]Q_H[/tex] = 16667 J/s

[tex]\frac{T_H}{T_H-T_C}=\frac{298}{298-279}[/tex]

= 15.684

[tex]Q_H = 16667 J/s[/tex]

16667 / W = 15.684

W= minimum power supplied  = 1062.7 W.

b )

If  [tex]T_C=283K[/tex]

[tex]\frac{T_H}{T_H-T_C}=\frac{298}{298-283}[/tex]

=19.87

[tex]\frac{Q_H}{W} = 19.87[/tex]

[tex]W=\frac{Q_H}{19.87}[/tex]

[tex]W=\frac{16667}{19.87}[/tex]

= 838.8 W .


Related Questions

Write a one paragraph essay about the importance of the different biomolecules in our life.

Answers

Answer:

#tried my bestt

do mark me as brainlist

Biomolecules are made by living organisms and they are made because they are functional. Biomolecules, or at least most of them, do not exist outside of living organisms because they are too complex to be created by chance chemical collisions. The odds of a single average sized protein to form by chance has been calculated at 1 out 10 to the 77th power. Biomolecules REQUIRE intelligent agency to form them.

The four main purposes of biomolecules are:

1. Structure (some proteins)

2. Energy storage and release (carbohydrates)  

3. Protective layers (lipids)

4. Information storage and communication (DNA, RNA, endocrines of numerous various types and manipulated molecules, such as fatty acids)

how to calculate motion​

Answers

Answer:

Distnace per unit time

Explanation:

Answer:

Newton's second law, which states that the force F acting on a body is equal to the mass m of the body multiplied by the acceleration a of its centre of mass, F = ma, is the basic equation of motion in classical mechanics.

Explanation:

verify the law of moment.​

Answers

Explanation:

TO VERIFY THE PRINCIPLE OF MOMENTS WHICH STATES THAT IF A NUMBER OF COPLANAR FORCES ACTIING ON A BODY S ,KEEP IT IN EQUILIBRIUM AND THEIR MOMENT ARE TAKEN ABOUT ANY POINT IN THEIR PLANE,THE SUM OF THE CLOCKWISE MOMENTS ,IS EQUAL TO SUM OF ANTICLOCKWISE MOMENT.

please mark me brainlist :)

Answer:

TO VERIFY THE PRINCIPLE OF MOMENTS WHICH STATES THAT IF A NUMBER OF COPLANAR FORCES ACTING ON A BODY, KEEP IT IN EQUILIBRIUM AND THEIR MOMENT ARE TAKEN ABOUT ANY POINT IN THEIR PLANE, THE SUM OF THE CLOCKWISE MOMENTS,  IS EQUAL TO SUM OF ANTICLOCKWISE MOMENT.

A laserbeam takes 24ms to travel from a rocket to a reflective surface of a planet and back to the rocket. How far, in miles, is the rocket from this planet’s surface?
A)2200 miles
B)3600 miles
C)2400 miles

please show work, thank you!

Answers

It’s a virus don’t believe it

Answer:B

Explanation:

8
The range of a target is found to be 20 km. A
shell leaves a gun with a velocity of 500 ms-'.
What must be the angle of elevation of the gun
if the ground is level?​

Answers

the angle of the gun needs to be at 25.8 degrees from the ground..

what type of wave travels through matter only??

Answers

A mechanical wave can only travel through matter.

Mechanical waves travel through water because waves transfer from one place to another

La temperatura de cambio de estado, ¿Puede ser igual para todos los materiales? Justifica comparando dos materiales

Answers

Answer:

No.

Explanation:

Para darnos cuenta de esto tenemos que pensar en lo siguiente:

Pensemos en un vaso de vidrio, lleno de agua hasta la mitad, la otra mitad puede ser manteca derretida

Si metemos el vaso en la heladera durante un par de horas, (sabemos que la manteca en la heladera se mantiene sólida) veremos que la manteca se solidificó en la parte de arriba, mientras que el agua sigue líquida.

Entonces encontramos dos compuestos con distintas temperaturas para cambio de fase, pero materiales es más específico, y puede referirse a materiales puros.

Entonces vamos a dos metales:

Primero tenemos una pieza de hierro y una de mercurio en el congelador (supongamos que ambas están a 0°C).

Ahora los sacamos del congelador y los dejamos llegar a temperatura ambiente.

Como bien sabemos, el mercurio es líquido a temperatura ambiente, entonces el mercurio va a sufrir un cambio de fase

Ahora pensemos en el hierro; claramente va a seguir siendo sólido a temperatura ambiente, entonces podemos ver dos materiales cuyo cambio de fase de sólido a líquido ocurre en distintas temperaturas, por lo que podemos concluir que no, la temperatura de cambio de estado no puede ser igual para todos los materiales, y esto se debe a que la estructura atómica de todos los materiales es diferente.

A 31 kg child is traveling at 4 m/s while sledding down a hill. What is the child's kinetic energy at the bottom of the hill?

Answers

Answer:

K.E = 248 J

Explanation:

Since the child is travelling at a given velocity. The kinetic energy of the child down the hill can be given by the following formula:

[tex]K.E = \frac{1}{2}mv^2\\[/tex]

where,

m = mass of the child = 31 kg

v = velocity of the child = 4 m/s

Therefore,

[tex]K.E = \frac{1}{2}(31\ kg)(4\ m/s)^2\\[/tex]

K.E = 248 J

the molecules in a solid state have _______ energy then molecules in a gas state​

Answers

Answer:

less

Explanation:

hope this helps....................:)

What causes the inner core to be solid?
A) Intense heat.
B) Intense pressure.
C) Because it is made of iron.
D) Because of it’s density.

Answers

your answer will be (B) - intense pressure.

Why should a physical quantity be measured?​

Answers

Answer:

It allows us to understand nature much more deeply than does qualitative description alone.

Explanation:

Without explaining the measurements, a quantity cannot always be measured.

Hope this helped, and please mark as Brainliest :)

Consider two walls, A and B, with the same surface areas and the same temperature drops across their thicknesses. The ratio of their thermal conductivities is kA/kB=4 and the ratio of the wall thickness is LA/LB=2. The ratio of heat transfer rates through the walls qA/qB is:


(a) 0.5

(b) 1

(c) 2

(d) 4

(e) 8

(f) None of them

Answers

Answer:

(c) 2

Explanation:

Heat transfer across the walls due to conduction is given by:

[tex]q = -KA\frac{\Delta T}{L}[/tex]

where,

q = heat transfer rate

K = thermal conductivity

A = Area

ΔT = change in temperature

L = thickness

For wall A:

[tex]q_A = -K_AA\frac{\Delta T}{L_A}[/tex]

For wall B:

[tex]q_B = -K_BA\frac{\Delta T}{L_B}[/tex]

Because the change of temperature and area of walls are the same. Dividing both terms:

[tex]\frac{q_A}{q_B} = \frac{\frac{K_A}{L_A} }{\frac{K_B}{L_B}}\\\\ \frac{q_A}{q_B} =\frac{\frac{K_A}{K_B} }{\frac{L_A}{L_B}}[/tex]

using values given in the question:

[tex]\frac{q_A}{q_B} = \frac{4}{2}\\\\\frac{q_A}{q_B} = 2[/tex]

Therefore, the correct answer is:

(c) 2

A kangaroo has a maximum gravitational potential energy during one jump of 770 J
Helppppp
When the kangaroo lands on the ground 14% of the maximum gravitational potential energy is transferred to elastic potential energy in one tendon.The tendon has an unstretched length of 35.0 cm
When the kangaroo lands on the ground the tendon stretches to a length of 42.0 cm
Calculate the spring constant of the tendon.
[5 marks]
Show ur working out

Answers

Answer:

k = 44000 N/m

Explanation:

Given the following data;

Maximum gravitational potential energy = 770 J

Elastic potential energy = 14% of 770 J = 14/100 * 770 = 107.8 J

Extension, x = 42 - 35 = 7cm to meters = 7/100 = 0.07 m

To find the spring constant, k;

The elastic potential energy of an object is given by the formula;

[tex] E.P.E = \frac {1}{2}kx^{2}[/tex]

Substituting into the equation, we have;

[tex] 107.8 = \frac {1}{2}*k*0.07^{2}[/tex]

[tex] 107.8 = \frac {1}{2}*k*0.0049 [/tex]

Cross-multiplying, we have;

[tex] 215.6 = k*0.0049 [/tex]

[tex] k = \frac {215.6}{0.0049} [/tex]

k = 44000 N/m

The spring constant of the tendon is 44000 N/m.

The following can be depicted from the question:

Elastic potential energy will be:

= 14% × 770J = 107.80 Joule.

The spring constant will be calculated thus:

107.8 = 1/2 × k × 0.07²

107.8 = 0.5 × k × 0.0049

k = 215.6 / 0.0049

k = 44000 N/m.

Therefore, the spring constant of the tendon is 44000 N/m.

Read related link on:

https://brainly.com/question/21163545

A tow truck pulls a 1,100kg car and accelerates at a rate of 3 m/s2. What is the force of the tow truck

Answers

Answer:

3300 N

Explanation:

From the question given above, the following data were obtained:

Mass (m) = 1100 Kg

Acceleration (a) = 3 m/s²

Force (F) =?

Force is defined by the following equation:

Force (F) = mass (m) × acceleration (a)

F = m × a

With the above formula, we can obtain the force of the tow truck as follow:

Mass (m) = 1100 Kg

Acceleration (a) = 3 m/s²

Force (F) =?

F = m × a

F = 1100 × 3

F = 3300 N

Therefore, the force of the tow truck is 3300 N

A high diver steps off a diving platform that is 10 meters above the water if no air resistance is present during the fall there will be a decrease in the divers what?

Answers

Answer:

Potential energy.

Explanation:

Potential energy can be defined as an energy possessed by an object or body due to its position.

Mathematically, potential energy is given by the formula;

[tex] P.E = mgh[/tex]

Where,

P.E represents potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per seconds square.

h represents the height measured in meters.

In this scenario, a high diver steps off a diving platform that is 10 meters above the water, if no air resistance is present during the fall there will be a decrease in the driver's potential energy. This is simply because the potential energy of all physical objects is greatly or highly dependent on acceleration due to gravity.

How much heat is required to change 200 mL of ice at -22°C (at typical Freezer temperature) into steam

Answers

Answer:

611.064 kJ

Explanation:

Given :

m = 200 mL = 200 g

Specific heat of ice = 2.06 J/g°C

Q = mcΔt

Δt = 0 - (-22) = 22

Q1 = 200 * 2.06 * 22 = 9064 J

Q2 = Melt 0 °C solid ice into 0 °C liquid water:

Q2 = m · ΔHf ; ΔHf = heat of fusion of water = 334j/g

Q2 = 200 * 334 = 66800 J

Q3 : Heat to convert from 0°C to 100°C

Q3 = mcΔt ; c = 4.19 J/g°C ; Δt = (100 - 0) = 100

Q3 = 200 * 4.19 * 100 = 83800 J

Q4: heat required to boil water to steam

Q = m · ΔHv

Hv = heat of vaporization of water = 2257 J/g

Q4 = 200 * 2257 = 451400 J

Total Q = Q1 + Q2 + Q3 + Q4

Q = 9064 + 66800 + 83800 + 451400

Q = 611,064 Joules

Q = 611.064 kJ

A wave oscillates with a period of 4.25 X 10-10 s. How many waves will strike a signal detector in 3 seconds?

Answers

Answer:

[tex]n=7.05\times 10^9[/tex] waves

Explanation:

Given that,

A wave oscillates with a period of [tex]4.25\times 10^{-10}\ s[/tex]

We need to find the number of waves that will strike a signal detector in 3 seconds.

We know that,

Frequency = (no. of oscillations)/time

Time period = time/(no. of oscillations)

Let there are n waves that will strike

So,

[tex]n=\dfrac{3}{4.25\times 10^{-10}}\\\\=7.05\times 10^9[/tex]

Hence, [tex]7.05\times 10^9[/tex] waves will strike in 3 seconds.

a hole in a copper plate has a diameter of 1.325 cm at 21C°. At what tempreture is the diameter equal to 1.164 cm

Answers

Answer:14C

Explanation:

A rocket experiences a 45,000 N force as it accelerates at 30 m/s/s. What is the mass of the rocket?

Answers

Answer:

15,00kg

Explanation:

here's your solution

=> force = 45,000N

=> acceleration = 30m/s^2

=> mass = ?

=> Mass = force/acceleration

=> mass = 45,000/30

=> mass = 15,00kg

hope it helps

Helppp please pleaseeee fr

Answers

Don’t click the link it’s not safe

12. A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of
60 kg, how long did it take him to reach that speed?

Answers

1/2 m/s2
30 Na




I hope this helps!

We have that  the Time  it took him to reach that speed is

t=1.2sec

From the question we are told

A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of  60 kg, how long did it take him to reach that speed?

Generally the equation for the   is mathematically given as

[tex]P=W/t[/tex]

Therefore

[tex]W=Pt\\\\W=250*t[/tex]

Where

[tex]W=f*d\\\\5*60=250*t\\\\t=\frac{5*60}{250}]\\\\t=1.2sec[/tex]

Therefore

Time  it took him to reach that speed is

t=1.2sec

For more information on this visit

https://brainly.com/question/21811998

What are the most essential skills in Team Handball and why?

Answers

Answer:

The most important skill in handball is passing or throwing

Explanation:

You need to be able to pass the ball with accuracy. Throwing and shooting drills are normally incorporated into every training session for handball.

Answer:

Explanation:

The most important skill in handball is passing or throwing. You need to be able to pass the ball with accuracy. Throwing and shooting drills are normally incorporated into every training session for handball.

PLEASE HELP ME I AM TIMED!

Answers

Answer:

I would say the 3rd one

Explanation:

Number 3 is correct the earth is tilted

Which combination of elements below results in a metallic bond?

Answers

Answer:

there isn't anything else posted to the question when you ask a question put a picture or write it out so people can see it

Explanation:

Helppppp
A kangaroo has a maximum gravitational potential energy during one jump of 770 J

When the kangaroo lands on the ground 14% of the maximum gravitational potential energy is transferred to elastic potential energy in one tendon.The tendon has an unstretched length of 35.0 cm
When the kangaroo lands on the ground the tendon stretches to a length of 42.0 cm
Calculate the spring constant of the tendon.
[5 marks]
Show ur working out

Answers

Answer:

44000n/m

Explanation:

In the nucleus ______________
tell cells what to do and how to change.

Answers

Answer:

i believe it is dna

Explanation:

if i remember correctly if the dna tells the cell what to do and how to do it

what’s answer? pls help will mark brainliest

Answers

Neutrons, the atomic mass can vary based on the number of neutrons

Calculate the distance of the end of a valley bearing in mind that the echo takes 0.7 seconds to be heard from the moment when the sound was produced.a

Answers

Answer:238m

Explanation:Distance = speed x time

Speed = 340 m/s

340 m/s x .07 s = 238m

What are some ways that humans depend on the ocean?

Answers

Answer:

A lot of the earth oxygen comes from the ocean around 50%-80%

Explanation:

Answer:

fishingswimming/entertainmentthe algae that gives us oxygenwater! It evaporates and gives us rainresearch

Explanation:

Light traveling through air encounter a second medium which slows the light to 2.7 x 10^8. What is the index of the medium?

Answers

Answer:

1.11

Explanation:

The index of the medium can be calculated using below formula

V= c/ n ............eqn(1)

Where V= velocity of the light is reduced to while traveling through the second medium= 2.7 x 10^8 m/s

n= index of the medium

c= speed of light= 3 x 10^8 m/s

Substitute for the values in eqn(1)

2.7 x 10^8 = (3 x 10^8 m/s)/ n

Making " n" subject of the formula, we have

n= (3 x 10^8 )/(2.7 x 10^8)

n= 1.11

Hence, the index of the medium is 1.11

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