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bonufazy [111]
2 years ago
11

A heat pump used to heat a house runs about one-third of the time. The house is losing heat at an average rate of 22,000 kJ/h. I

f the COP of the heat pump is 2.8, determine the power the heat pump draws when running.
Physics
1 answer:
Natali5045456 [20]2 years ago
5 0

The power that heat pump draws when running will be 6.55 kj/kg

A heat pump is a device that uses the refrigeration cycle to transfer thermal energy from the outside to heat a building (or a portion of a structure).

Given a heat pump used to heat a house runs about one-third of the time. The house is losing heat at an average rate of 22,000 kJ/h and if the COP of the heat pump is 2.8

We have to determine the power the heat pump draws when running.

To solve this question we have to assume that the heat pump is at steady state

Let,

Q₁ = 22000 kj/kg

COP = 2.8

Since heat pump used to heat a house runs about one-third of the time.

So,

Q₁ = 3(22000) = 66000 kj/kg

We known the formula for cop of heat pump which is as follow:

COP = Q₁/ω

2.8 = 66000 / ω

ω = 66000 / 2.8

ω = 6.66 kj/kg

Hence the power that heat pump draws when running will be 6.55 kj/kg

Learn more about heat pump here :

brainly.com/question/1042914

#SPJ4

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Elan Coil [88]

Answer:

Efficiency = 71%

Explanation:

Given the following data:

Output energy = 250 Joules

Input energy = 350 Joules

To find efficiency;

Efficiency = \frac {Out-put \; energy}{In-put \; energy} * 100

Substituting into the equation, we have;

Efficiency = \frac {250}{350} * 100

Efficiency = 0.7143 * 100

Efficiency = 71.43 ≈ 71%

Therefore, the efficiency of the candle is 71 percent.

4 0
3 years ago
Why are springs made of steel and not of copper.​
torisob [31]

Answer:

Springs are made of a variety of materials including copper and various forms of steel. The most common is high carbon steel as it is cheap, easy to work and a couple of other important properties.

Copper springs exist as well, but copper is more expensive than steel. However, in an environment where corrosion resistance is important, copper springs are a good alternative.

Explanation:

8 0
3 years ago
Read 2 more answers
You drop a steel ball bearing, with a radius of 2.40 mm, into a beaker of honey. Note that honey has a viscosity of 6.00 Pa/s an
Stells [14]

Answer:

The “terminal speed” of the ball bearing is 5.609 m/s

Explanation:

Radius of the steel ball R = 2.40 mm

Viscosity of honey η = 6.0 Pa/s

\text { Viscosity has Density } \sigma=1360 \mathrm{kg} / \mathrm{m}^{3}

\text { Steel has a density } \rho=7800 \mathrm{kg} / \mathrm{m}^{3}

\left.\mathrm{g}=9.8 \mathrm{m} / \mathrm{s}^{2} \text { (g is referred to as the acceleration of gravity. Its value is } 9.8 \mathrm{m} / \mathrm{s}^{2} \text { on Earth }\right)

While calculating the terminal speed in liquids where density is high the stokes law is used for viscous force and buoyant force is taken into consideration for effective weight of the object. So the expression for terminal speed (Vt)

V_{t}=\frac{2 \mathrm{R}^{2}(\rho-\sigma) \mathrm{g}}{9 \eta}

Substitute the given values to find "terminal speed"

\mathrm{V}_{\mathrm{t}}=\frac{2 \times 0.0024^{2}(7800-1360) 9.8}{9 \times 6}

\mathrm{V}_{\mathrm{t}}=\frac{0.0048 \times 6440 \times 9.8}{54}

\mathrm{V}_{\mathrm{t}}=\frac{302.9376}{54}

\mathrm{V}_{\mathrm{t}}=5.609 \mathrm{m} / \mathrm{s}

The “terminal speed” of the ball bearing is 5.609 m/s

7 0
3 years ago
the pressure of gas in a cylinder is 70 kilopascals. if the volume of the cylinder is reduced from 8.0 liters to 4.0 liters, wha
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By Boyle's law:

P₁V₁ = P₂V₂

70*8 = P<span>₂*4

</span>P<span>₂*4 = 70*8
</span>
P<span>₂ = 70*8/4 = 140
</span>
P<span>₂ = 140 kiloPascals.</span>
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3 years ago
In the Bohr model of the hydrogen atom, the speed of the electron is approximately 2.2 106 m/s.
Murrr4er [49]

The central force acting on the electron as it revolves in a circular orbit is 9.52 \times 10^{-8} \ N.

The given parameters;

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<em />

The central force acting on the electron as it revolves in a circular orbit is calculated as follows;

F = \frac{M_e v^2}{r} \\\\

where;

M_e is mass of electron = 9.11 x 10⁻³¹ kg

F = \frac{(9.11 \times 10^{-31}) \times(2.2\times 10^6)^2 }{4.63 \times 10^{-11}} \\\\F = 9.52 \times 10^{-8} \ N

Thus, the central force acting on the electron as it revolves in a circular orbit is 9.52 \times 10^{-8} \ N.

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