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3 years ago

Hey can anyone help me wih these questions please

Physics

1 answer:

Pavel [41]3 years ago

4 0

<span>The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in.An object will sink if it is more dense than the liquid it is placed in.

Since the above solid sinks to the bottom it reflects that the object is less dense that the water.

Hope this answers your question</span>

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What are the two distinct ways in which energy moves outward from the solar core to photosphere?

butalik [34]

Answer:

The energy may be carried in the form of (1) radiation, where energy travels in the form of light, and (2) convection, where energy is carried by physical motion of upwelling solar gas.

Explanation:

6 0

2 years ago

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

erma4kov [3.2K]

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

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

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

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

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

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

$E = K (40 - 30)^2$

=> $E = 100K$

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

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

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

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

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.

4 0

2 years ago

Ditto sound waves espace room answers please I need this urgently

lord [1]

The actual question should be did the sound waves escape room?

Yes they can escape the room

Sound always needs a medium to travel through
If you close the room form all where that even air can't go outside you will be able to hear no sound coming from room .

6 0

1 year ago

Mention the name of the following frequencies depending upon their values a) 12Hz b) 20100Hz

Kaylis [27]

It can be a) 12Hz.................

5 0

3 years ago

An x-ray beam of a certain wavelength is incident on a crystal, at 30.7° to a certain family of reflecting planes of spacing 33.

klemol [59]

Answer:

λ=34.068pm

Explanation:

Wavelength λ=2dsinθ

λ=2(33.4pm)sin30.7

λ=2(33.4pm) * 0.510

λ=66.8* sin30.7

λ=66.8*0.510

λ=34.068pm

X-rays are usually produced by charged particles that are accelerating or decelerating such as a beam of electrons striking a metal plate in an X-ray tube.

3 0

2 years ago

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