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luda_lava [24]
2 years ago
13

7. How much time does it take a person to walk 8

Physics
1 answer:
Mashcka [7]2 years ago
5 0
So it’s 4km/h

We divide 8/4

2 hours
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When a 20-V emf is placed across two resistors in series, a current of 2.0 A is present in each of the resistors. When the same
ehidna [41]

Answer:

7.24 ohm

Explanation:

Let R1 and R2 are resistance of two resistors.

Emf=E=20 V

Current,I=2 A

Current,I'=10 A

We have to find the magnitude of the greater of the two resistances.

In series

R=R_1+R_2

V=IR

By using the formula

20=2(R_1+R_2)

R_1+R_2=\frac{20}{2}=10...(1)

In parallel

\frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2}

\frac{1}{R}=\frac{R_2+R_1}{R_1R_2}

R=\frac{R_1R_2}{R_1+R_2}

20=10(\frac{R_1R_2}{R_1+R_2}

2=\frac{R_1R_2}{10}

R_1R_2=20

R_2=\frac{20}{R_1}

Substitute the value

\frac{20}{R_1}+R_1=10

R^2_1+20=10R_1

R^2_1-10R_1+20=0

R_1=\frac{10\pm\sqrt{(-10)^2-4(20)}}{2}

By using quadratic formula

x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

R_1=\frac{10\pm 2\sqrt 5}{2}

R_1=\frac{10+2\sqrt 5}{2}=5+\sqrt 5=7.24 ohm

R_1=\frac{10-2\sqrt 5}{2}=2.76 ohm

Substitute the value

R_2=\frac{20}{7.24}=2.76 ohm

R_2=\frac{20}{2.76}=7.24 ohm

Hence, the magnitude of the greater of the two resistance=7.24 ohm

8 0
3 years ago
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When a certain element is excited with electricity, we see three main lines in its emission spectrum: two red lines and one oran
Eddi Din [679]
The absorption spectrum would have all the wavelengths of the light source but would have black lines where the two red and one orange lines were in the emission spectrum
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3 years ago
How does a steam engine do work?
Viktor [21]
Steam enters a cylinder—- A
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N capacitors are connected in parallel to form a "capacitor circuit". The capacitance of first capacitor is C, second one is C/2
liberstina [14]

Answer:

2C

Explanation:

The equivalent capacitance of a parallel combination of capacitors is the sum of their capacitance.

So, if the capacitance of each capacitor is half the previous one, we have a geometric series with first term = C and rate = 0.5.

Using the formula for the sum of the infinite terms of a geometric series, we have:

Sum = First term / (1 - rate)

Sum = C / (1 - 0.5)

Sum = C / 0.5 = 2C

So the equivalent capacitance of this parallel connection is 2C.

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An airplane was moving 1200 km per minute traveling in a north-to-south direction when they were spotted by air traffic control.
Feliz [49]

Its velocity was 20 km/s southward

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