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3 years ago

9

Wire B has twice the length and twice the radius of wire A. both wires are made from the same material. if wire A has a resistan

ce R, what is the resistance of wire B?

1 answer:

otez555 [7]3 years ago

3 0

Answer:

Hello There!!

Explanation:

1/2R because wire B has twice the radius,it has four times the cross-sectional area of wire A.

hope this helps,have a great day!!

~Pinky~

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A flashlight contains a battery of two cells in series, with a bulb of resistance 12 Ohms. The internal resistance of each cell

Elina [12.6K]

Answer:

1.5024

Explanation:

Draw a diagram. Put the two cells in series. Now draw 3 resistors. Two of them equal 0.26 ohms each. The third one is the lightbulb which is 12 ohms.

R = 0.26 + 0.26 + 12 = 12.52

The bulb has a voltage of 2.88 volts across it. You can get the current from that.

i = E / R

i = 2.88 / 12 =

i = 0.24 amps.

Now you can get the voltage drop across the two cells.

E = ?

R = 0.26

i = 0.24 amps

E = 0.26 * 0.24

E = 0. 0624

Finally divide the 2.88 by 2 to get 1.44

Each cell has an emf of 1.44 + 0.0624 = 1.5024

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3 years ago

________ In many cartoon shows, a character runs off a cliff, realizes his predicament, and lets out a scream. He continues to s

IrinaVladis [17]

Answer:

Here the source is moving away from the observer so frequency will be smaller than the actual frequency and since the speed is increasing so the frequency is decreasing with time so correct answer is

D) lower than the original pitch and decreasing as he falls.

Explanation:

As we know by the Doppler's effect of sound we have

so we will have

$f = f_o(\frac{v}{v + v_s})$

so here when source moves away from the observer with a some speed then the frequency of the sound observed by the observer is smaller than the actual frequency

Here we know that the speed of the source is increasing with time as the source is falling under gravity

So we can say that the pitch of the sound will decrease with time

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4 years ago

A merry-go-round is shaped like a uniform disk and has moment of inertia of 50,000 kg m 2 . It is rotating so that it has an ang

lapo4ka [179]

Answer:

r = 20 m

Explanation:

The formula for the angular momentum of a rotating body is given as:

L = mvr

where,

L = Angular Momentum = 10000 kgm²/s

m = mass

v = speed = 2 m/s

r = radius of merry-go-round

Therefore,

10000 kg.m²/s = mr(2 m/s)

m r = (10000 kg.m²/s)/(2 m/s)

m r = 5000 kg.m ------------- equation 1

Now, the moment of inertia of a solid uniform disc about its axis through its center is given as:

I = (1/2) m r²

where,

I = moment of inertia = 50000 kg.m²

Therefore,

50000 kg.m² = (1/2)(m r)(r)

using equation 1, we get:

50000 kg.m² = (1/2)(5000 kg.m)(r)

(50000 kg.m²)/(2500 kg.m) = r

<u>r = 20 m</u>

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3 years ago

Tarzan swings on a 26.2 m long vine initially inclined at an angle of 28° from the vertical. (a) What is his speed at the bottom

Marianna [84]

Answer

given,

length of the swing = 26.2 m

inclined at an angle = 28°

let, the initial height of the Tarzan be h

h = L (1 - cos θ)

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final velocity of Tarzan = v_f

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$mgh_i + \dfrac{1}{2}mv_i^2= mgh_f + \dfrac{1}{2}mv_f^2$

$mgh_i + 0 = 0 + \dfrac{1}{2}mv_f^2$

$mgh_i = \dfrac{1}{2}mv_f^2$

$v_f = \sqrt{2gh_i}$

$= \sqrt{2gL(1- cos\theta)}$

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= 7.75 m/s

the speed tarzan at the bottom of the swing

v_f = 7.75 m/s

b)initial speed of the = 3 m/s

$mgh_i + \dfrac{1}{2}mv_i^2= mgh_f + \dfrac{1}{2}mv_f^2$

$mgh_i + 0 = 0 + \dfrac{1}{2}mv_f^2$

$mgh_i+ \dfrac{1}{2}mv_i^2 = \dfrac{1}{2}mv_f^2$

$gh_i+ \dfrac{1}{2}v_i^2 = \dfrac{1}{2}v_f^2$

$v_f = \sqrt{v_1^2+2gh_i}$

$v_f = \sqrt{3^2+2\times 9.8 \times (1- cos 28^0)}$

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Choice-a is a very rubbery, imprecise, ambiguous, slippery statement. But it's probably less wrong than any of the other choices on the list.

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3 years ago