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Diano4ka-milaya [45]
2 years ago
14

Find the time taken if the speed of a train increased rom 72km/h to 90km/h for 234km

Physics
2 answers:
bagirrra123 [75]2 years ago
8 0

Answer:

Explanation:

s = s₀ + v₀t + ½at²

Let s₀ = 0 be the position in km where acceleration starts,

Let t be in hours

a = (90 - 72) / t = 18/t  km/hr²

234 = 0 + 72t + ½(18/t)t²

234 = 72t + 9t

234 = 81t

t = 2.88888... ≈ 2.89 hr

Katarina [22]2 years ago
7 0

Answer:

2.89 hours

Explanation:

given :

Vo = 72 km/h

Vt = 90 km/h

S = 234 km

find : the time taken (t) = ?

solution :

2.a.s = Vt² - Vo²

2.a.(234) = 90²- 72²

468.a = 8100 - 5184

= 2916

a = 2916/468 = 6.23 km/h²

so,

t = (Vt-Vo) /a

= (90-72)/ 6.23

= 18/ 6.23

= 2.89 hours

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Answer:

N_{2}=20 turns

Explanation:

The given case is a step down transformer as we need to reduce 120 V to 6 V.

number of turns on primary coil N_{P}= 400

current delivered by  secondary coil  I_{S}= 500 mA

output voltage = 6 V (rms)

we know that

I_{p}=\frac{V_{out}}{V_{in}\times I_{s}}

putting values we get

I_{p}=\frac{6}{120\times 0.5}

I_{p}= 0.1 A

to calculate number of turns in secondary

\frac{N_{2}}{400} =\frac{6}{120}

therefore, N_{2}=20 turns

5 0
3 years ago
ANSWER ASAP PLS
posledela

Answer:

<h3>JAWAB SECEPATNYA pliss</h3><h3 /><h3>Anda memiliki rangkaian paralel 10 volt, dengan 2 resistor di atasnya. Berapakah tegangan pada</h3><h3>resistor pertama? Di seberang kedua?</h3><h3 /><h3>(saya akan menandai tercerdas tolong bantu)</h3>

Explanation:

Hukum Ohm

= tegangan

= kuat arus

= ketahanan

Kalau kamu mau mencari tegangan listrik, kamu gunakan rumus V = I.R. Kalau ternyata kamu perlu mencari kuat arus listrik, maka gunakan rumus I = V/R. Nah, kalau yang kamu cari adalah hambatan listrik, maka gunakan rumus R = V/I.

4 0
2 years ago
The granulation pattern that astronomers have observed on the surface of the Sun tells us that: a. the Sun is a lot cooler on th
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Answer:

c. hot material must be rising from the Sun's hotter interior

Explanation:

Granulation is the grainy appearance of the solar photosphere produced by the top of the convection cells in the sun.

The grainy appearance are produced by granules on the photosphere of the sun and granules are caused by convection currents of plasma within the sun's convection zone.

The interior of these granules are brighter (and thus hotter) than the exterior of the granules which are darker.

<u>So, the granulation pattern that astronomers have observed on the surface of the Sun tells us that hot material must be rising from the Sun's hotter interior.</u>

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3 years ago
Which statement describes a scientific theory?
PSYCHO15rus [73]

Answer:

A theory changes based on new observations and testing.

Explanation:

A scientific theory is a product of multiple trials and repeated experiments. It usually follows after carefully conducting and testing the validity of the hypothesis.

A scientific theory provides an explanation into how something behaves.

A law just states a finding will not explain it.

Most theories are tenable and can be improved upon when new observations and testing are carried out.

4 0
3 years ago
A power plant running at 39 % efficiency generates 330 MW of electric power. Part A At what rate (in MW) is heat energy exhauste
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By definition of energy efficiency, we derive an expression for the energy rate exhausted to the river (Q_{out}), in megawatts:

Q_{out} = Q_{in} - W

Q_{out} = \left(\frac{1}{\eta}-1 \right)\cdot W(1)

Where:

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If we know that \eta = 0.39 and W = 330\,MW, then the energy rate exhausted to the river is:

Q_{out} = \left(\frac{1}{0.39}-1 \right)\cdot (330\,MW)

Q_{out} = 516.154\,MW

516.154 megawatts of heat are <em>exhausted</em> to the river that cools the plant.

We kindly to check this question on first law of thermodynamics: brainly.com/question/3808473

7 0
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