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3 years ago

10

If a fast-moving car making a loud noise approaches and moves past the person, what will happen as the distance between the two

increases?
A. The pitch of the sound being heard by the person will appear to be higher than the pitch of the source.
B. The frequency of the sound waves reaching the person's ear will be greater than the frequency of the waves leaving the car.
C. The pitch of the sound being heard by the person will appear to be lower than the pitch of the source.
D. The pitch and frequency of the sound waves reaching the person's ear will remain unchanged.

2 answers:

densk [106]3 years ago

5 0

C. The Pitch of the sound being heard by the person will appear to be lower than the pitch of the source. I hope this is right

vladimir2022 [97]3 years ago

3 0

The answer is B.
The frequency will be greater

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Is silver magnetic or not ?

evablogger [386]

Answer:

Yes, but its magnetic power is very weak so its not that noticeable to the average person whos not paying attention.

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2 years ago

A cosmic ray (an electron or nucleus moving ar speeds close to the speed of light) travels across the Milky Way at a speed of 0.

Fiesta28 [93]

Answer:

Cosmic ray's frame of reference: 99,875 years

Stationary frame of reference: 501,891 years

Explanation:

First of all, we convert the distance from parsec into metres:

$d=30,000 pc =9.26\cdot 10^{20} m$

The speed of the cosmic ray is

$v=0.98 c$

where

$c=3.0 \cdot 10^8 m/s$ is the speed of light. Substituting,

$v=(0.98)(3.0\cdot 10^8)=2.94\cdot 10^8 m/s$

And so, the time taken to complete the journey in the cosmic's ray frame of reference (called proper time) is:

$T_0 = \frac{d}{v}=\frac{9.26\cdot 10^{20}}{2.94\cdot 10^8}=3.15\cdot 10^{12} s$

Converting into years,

$T_0 = \frac{3.15\cdot 10^{12}}{(365\cdot 24\cdot 60 \cdot 60}=99,875 years$

Instead, the time elapsed in the stationary frame of reference is given by Lorentz transformation:

$T=\frac{T_0}{\sqrt{1-(\frac{v}{c^2})^2}}$

And substituting v = 0.98c, we find:

$T=\frac{99,875}{\sqrt{1-(\frac{0.98c}{c})^2}}=501,891 years$

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3 years ago

To practice problem-solving strategy 22.1: gauss's law. an infinite cylindrical rod has a uniform volume charge density ρ (where

BabaBlast [244]

Let say the point is inside the cylinder

then as per Gauss' law we have

$\int E.dA = \frac{q}{\epcilon_0}$

here q = charge inside the gaussian surface.

Now if our point is inside the cylinder then we can say that gaussian surface has charge less than total charge.

we will calculate the charge first which is given as

$q = \int \rho dV$

$q = \rho * \pi r^2 *L$

now using the equation of Gauss law we will have

$\int E.dA = \frac{\rho * \pi r^2* L}{\epcilon_0}$

$E. 2\pi r L = \frac{\rho * \pi r^2* L}{\epcilon_0}$

now we will have

$E = \frac{\rho r}{2 \epcilon_0}$

Now if we have a situation that the point lies outside the cylinder

we will calculate the charge first which is given as it is now the total charge of the cylinder

$q = \int \rho dV$

$q = \rho * \pi r_0^2 *L$

now using the equation of Gauss law we will have

$\int E.dA = \frac{\rho * \pi r_0^2* L}{\epcilon_0}$

$E. 2\pi r L = \frac{\rho * \pi r_0^2* L}{\epcilon_0}$

now we will have

$E = \frac{\rho r_0^2}{2 \epcilon_0 r}$

7 0

3 years ago

GAMMA RAYS<br> What are some applications of gamma rays? In other words, what can we use them for?

r-ruslan [8.4K]

Answer:

Explanation:

Gamma-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells. Also, industry (sterilization and disinfection) and the nuclear industry.

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3 years ago

What is the average power developed by a motor as it lifts a 400.-kilogram mass at constant speed through a vertical distance of

Tomtit [17]

Answer:

The average power developed by a motor is 4905 Watts.

Explanation:

The average power is given by:

$P = \frac{W}{t}$

Where:

W: is the work

t: is the time = 8.0 s

First, let's find the work:

$W = F*d$

Where:

F: is the force

d: is the displacement = 10.0 m

The force is in the vertical motion, and since the movement of the mass is at constant speed the force is:

$F = mg = 400 kg*9.81 m/s^{2} = 3924 N$

Hence, the average power is:

$P = \frac{F*d}{t} = \frac{3924 N*10.0 m}{8.0 s} = 4905 J/s = 4905 W$

Therefore, the average power developed by a motor is 4905 Watts.

I hope it helps you!

3 0

3 years ago