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3 years ago

1. Alexandra and Rachel are on a train that sounds a whistle at a constant frequency as

Physics

2 answers:

exis [7]3 years ago

6 0

Answer: the answer would be C trust me i took the test if its not that its b

hope that helps

Explanation: i took the test

Zepler [3.9K]3 years ago

5 0

answer:

a) lower because the sound-wave fronts reach the platform at a frequency lower than the frequency at which they are produced

explanation :3

If the train is leaving the train station, then the people who are standing on the platform would hear a sound with a lower frequency since the train is moving further away. ^^

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An infinitely long straight wire has a uniform linear charge density of Derive the 4. equation for the electric field a distance

marshall27 [118]

Answer:

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

Explanation:

Let the linear charge density of the charged wire is given as

$\frac{q}{L} = \lambda$

here we can use Gauss law to find the electric field at a distance r from wire

so here we will assume a Gaussian surface of cylinder shape around the wire

so we have

$\int E. dA = \frac{q}{\epsilon_0}$

here we have

$E \int dA = \frac{\lambda L}{\epsilon_0}$

$E. 2\pi r L = \frac{\lambda L}{\epsilon_0}$

so we have

$E = \frac{\lambda}{2\pi \epsilon_0 r}$

4 0

3 years ago

A circular loop of wire with radius 2.00 cm and resistance 0.600 Ω is in a region of a spatially uniform magnetic field B⃗ that

Anika [276]

Answer:

Incomplete questions

Let assume we are asked to find

Calculate the induced emf in the coil at any time, let say t=2

And induced current

Explanation:

Flux is given as

Φ=NAB

Where

N is number of turn, N=1

A=area=πr²

Since r=2cm=0.02

A=π(0.02)²=0.001257m²

B=magnetic field

B(t)=Bo•e−t/τ,

Where Bo=3T

τ=0.5s

B(t)=3e(−t/0.5)

B(t)=3exp(-2t)

Therefore

Φ=NAB

Φ=0.001257×3•exp(-2t)

Φ=0.00377exp(-2t)

Now,

Induce emf is given as

E= - dΦ/dt

E= - 0.00377×-2 exp(-2t)

E=0.00754exp(-2t)

At t=2

E=0.00754exp(-4)

E=0.000138V

E=0.138mV

b. Induce current

From ohms laws

V=iR

Given that R=0.6Ω

i=V/R

i=0.000138/0.6

i=0.00023A

i=0.23mA

5 0

3 years ago

How have earthquake data been used to explore the size of convection currents in the mantle?

nadezda [96]

Vibration waves from earth quakes travel through the earth and have measurable speed. And the different temperatures and fluidity of the various regions of the mantle will change that speed and or reflect the vibration waves in different directions. With multiple vibration sensors around the world the time that it takes for vibrations to travel from one part of the world to another will tell you what is inside.

8 0

3 years ago

An organism’s scientific name consists of a. its class name and its family name. b. its kingdom name and its phylum name. c. its

mr Goodwill [35]

An organism scientific name consist of : C. its genus name and its species name
The first part of the name is taken from the Genus and the second part of the name is taken from the species
hope this helps

7 0

3 years ago

You have a 2m long wire which you will make into a thin coil with N loops to generate a magnetic field of 3mT when the current i

Anni [7]

Answer:

radius of the loop = 7.9 mm

number of turns N ≅ 399 turns

Explanation:

length of wire L= 2 m

field strength B = 3 mT = 0.003 T

current I = 12 A

recall that field strength B = μnI

where n is the turn per unit length

vacuum permeability μ = $4\pi *10^{-7} T-m/A$ = 1.256 x 10^-6 T-m/A

imputing values, we have

0.003 = 1.256 x 10^−6 x n x 12

0.003 = 1.507 x 10^-5 x n

n = 199.07 turns per unit length

for a length of 2 m,

number of loop N = 2 x 199.07 = 398.14 ≅ 399 turns

since there are approximately 399 turns formed by the 2 m length of wire, it means that each loop is formed by 2/399 = 0.005 m of the wire.

this length is also equal to the circumference of each loop

the circumference of each loop = $2\pi r$

0.005 = 2 x 3.142 x r

r = 0.005/6.284 = $7.9*10^{-4} m$ = 0.0079 m = 7.9 mm

8 0

3 years ago