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Zarrin [17]
3 years ago
9

7. Which phase changes require a gain of energy (heat)?

Physics
2 answers:
Keith_Richards [23]3 years ago
7 0

Answer:

c

Explanation:

adell [148]3 years ago
4 0

Answer:

C.

Explanation:

When there is heat the water turns into vapour if not covered but will turn back to water if covered (condensation)

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The main water line enters a house on the first floor. The line has a gauge pressure of 1.94 x 105 Pa. (a) A faucet on the secon
Ad libitum [116K]

Answer

given,

gauge pressure =   1.94 x 10⁵ Pa

Pressure due to 4.90 m column of water

= ρ g h

= (4.90) x  (1000)  x (9.8) Pa

= 48020 Pa

Gauge pressure of second floor faucet

= 1.94 x 10⁵Pa - 48020 Pa

P_g= 145980 Pa

( b )

Let h = height of faucet from which no water can flow even if open

P = ρ g h

1.94 x 10⁵  = h x(1000) x (9.8)

h = 19.79 m

4 0
3 years ago
A load of 1 kW takes a current of 5 A from a 230 V supply. Calculate the power factor.
Pachacha [2.7K]

Answer:

Power factor = 0.87 (Approx)

Explanation:

Given:

Load = 1 Kw = 1000 watt

Current (I) = 5 A

Supply (V) = 230 V

Find:

Power factor.

Computation:

Power factor = watts / (V)(I)

Power factor = 1,000 / (230)(5)

Power factor = 1,000 / (1,150)

Power factor = 0.8695

Power factor = 0.87 (Approx)

6 0
3 years ago
The speed of water flowing through a hose increases from 2.05 m/s to 31.4 m/s as it goes through the nozzle. What is the pressur
Nimfa-mama [501]

The pressure in the hose as the speed of water changes from 2.05 m/s to 31.4 m/s as it goes through the nozzle is 5.92 × 10⁵ N/m².

Given:

The flow of water through the hose initially, v₁ = 2.05 m/s

The flow of water through the hose initially, v₂ = 31.4 m/s

Calculation:

From Bernoulli's equation we have:

P₁ + 1/2 ρv₁² + ρgh₁ = P₂ + 1/2 ρv₂² + ρgh₂

where P₁ is atmospheric pressure

           P₂ is the pressure in the hose

           ρ is the density of the fluid

           h₁ is the initial height

           h₂ is the final height

           v₁ is the initial velocity of the fluid

           v₂ is the final velocity of the fluid  and

           g is the acceleration due to gravity

Re-arranging the above equation we get:

P₂ = P₁ + 1/2 ρ(v₁²-v₂²) + ρg (h₁-h₂)

Applying values in the above equation we get:

P₂ = P₁ + 1/2 ρ(v₁²-v₂²) + ρg (0)

    = (1.01 × 10⁵ Pa)+ 1/2 (10³ g/m³) [(31.4m/s)²-(2.05 m/s)²]

    = (1.01 × 10⁵ Pa)+ 1/2 (10³ g/m³) [981.7575]

    = (1.01 × 10⁵ Pa)+ (4.91 × 10⁵ Pa)

    = 5.92 × 10⁵ Pa

    = 5.92 × 10⁵ N/m²

Therefore, the pressure in the hose is 5.92 × 10⁵ N/m².

Learn more about Bernoulli's equation here:

<u>brainly.com/question/9506577</u>

#SPJ4

6 0
1 year ago
Calculate the change in internal energy of the following system: A balloon is cooled by removing 0.659 kJ of heat. It shrinks on
bixtya [17]
<h2>Answer:</h2>

-310J

<h2>Explanation:</h2>

The change in internal energy (ΔE) of a system is the sum of the heat (Q) and work (W) done on or by the system. i.e

ΔE = Q + W       ----------------------(i)

If heat is released by the system, Q is negative. Else it is positive.

If work is done on the system, W is positive. Else it is negative.

<em>In this case, the system is the balloon and;</em>

Q = -0.659kJ = -695J    [Q is negative because heat is removed from the system(balloon)]

W = +385J  [W is positive because work is done on the system (balloon)]

<em>Substitute these values into equation (i) as follows;</em>

ΔE = -695 + 385

ΔE = -310J

Therefore, the change in internal energy is -310J

<em>PS: The negative value indicates that the system(balloon) has lost energy to its surrounding, thereby making the process exothermic.</em>

<em />

<em />

5 0
3 years ago
Sound waves that enter the ear canal are directed to the ____, causing it to vibrate.
andre [41]

According to the research, the correct option the eardrum. Sound waves that enter the ear canal are directed to the <u>eardrum</u>, causing it to vibrate.

<h3>What is the eardrum?</h3>

It is the membrane found in the middle ear of vertebrate animals, separating this sector from the external auditory canal.

When sound waves enter through the external auditory canal, the eardrum vibrates, transmitting its movement to the middle ear through a series of bones and in this way, the pressure change is transformed into a mechanical movement.

Therefore, we can conclude that according to the research, the correct option is the eardrum. Sound waves that enter the ear canal are directed to the <u>eardrum</u>, causing it to vibrate.

Learn more about the eardrum here: brainly.com/question/12770491

#SPJ1

4 0
1 year ago
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