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3 years ago

9

A stationary speed gun emits a microwave beam at 2.10x10^10 Hz. It reflects off a car and returns 638 Hz lower. What is the spee

d of the car? (Unit=m/s)

1 answer:

stiv31 [10]3 years ago

6 0

Answer:

The answer is 4.55 m/s!

Explanation:

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A solenoid 25.0 cmcm long and with a cross-sectional area of 0.550 cm^2 contains 460 turns of wire and carries a current of 90.0

ankoles [38]

Answer:

a. B = 0.20T

b. u = 17230.6 J/m³

c. E = 0.236J

d. L = 5.84*10^-5 H

Explanation:

a. In order to calculate the magnetic field in the solenoid you use the following formula:

$B=\frac{\mu_o n i}{L}$ (1)

μo: magnetic permeability of vacuum = 4π*10^-7 T/A

n: turns of the solenoid = 460

L: length of the solenoid = 25.0cm = 0.25m

i: current = 90.0A

You replace the values of the parameters in the equation (1):

$B=\frac{(4\pi*10^{-7}T/A)(460)(90.0A)}{0.25m}=0.20T$

The magnetic field in the solenoid is 0.20T

b. The magnetic permeability of air is approximately equal to the magnetic permeability of vacuum. To calculate the energy density in the solenoid you use:

$u=\frac{B^2}{2\mu_o}=\frac{(0.20T)^2}{2(4\pi*10^{-7}T/A)}=17230.6\frac{J}{m^3}$

The energy density is 17230.6 J/m³

c. The total energy contained in the solenoid is:

$E=uV$ (2)

V is the volume of the solenoid and is calculated by assuming the solenoid as a perfect cylinder:

$V=AL$

A: cross-sectional area of the solenoid = 0.550 cm^2 = 5.5*10^-5m^2

$V=(5.5*10^{-5}m^2)(0.25m)=1.375*10^{-5}m^3$

Then, the energy contained in the solenoid is:

$E=(17230.6J/m^3)(1.375*10^{-5}m^3)=0.236J$

The energy contained is 0.236J

d. The inductance of the solenoid is calculated as follow:

$L=\frac{\mu_o N^2 A}{L}=\frac{(4\pi*10^{-7}T/A)(460)^2(5.5*10^{-5}m^2)}{0.25m}\\\\L=5.84*10^{-5}H$

The inductance of the solenoid is 5.84*10^-5 H

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3 years ago

A cart rolling at ground level has K = 1500 J. It comes to a ramp, rolls up the ramp to an elevated platform. When it's on this

Black_prince [1.1K]

The potential energy Wood be 1000

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3 years ago

Calculate Speed The 2-kg metal ball moving at a speed of 3 m/s strikes a 1-kg wooden ball that is at rest. After the collision,

enot [183]

Answer:

53466kg.

Explanatiokn:

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2 years ago

Electrolytes are considered ________ when placed in a solution and allow for adequate conduction of ________ charges.

DedPeter [7]

Answer:

Electrolytes are considered ions when placed in a solution and allow for adequate conduction of particle charges.

Explanation:

Electrolytes are substances that, when are dissolved in solution, separates into electrical positive charges (cations) and electrical negative charges (anions) which are known as ions.

These ions have an adequate capacity to conduct particle charges and, therefore electricity.

Sodium, calcium, phosphate and potassium, are examples of electrolytes.

<u>Hence, the correct answer is:</u>

Electrolytes are considered ions when placed in a solution and allow for adequate conduction of particle charges.

I hope it helps you!

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3 years ago

What are some ways scientists can study the seafloor?

TiliK225 [7]

Answer: A device records the time it takes sound waves to travel from the surface to the ocean floor and back again. Sound waves travel through water at a known speed. Once scientists know the travel time of the wave, they can calculate the distance to the ocean floor.

Explanation:

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3 years ago

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