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3 years ago

Which of the following is not true about minerals?

Physics

2 answers:

mezya [45]3 years ago

6 0

Answer:

I think it's A but I'm not sure

Nikolay [14]3 years ago

6 0

A the always include oxygen and silicon

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A surface receiving sound is moved from its original position to a position three times farther away from the source of the soun

vazorg [7]

Answer:

c. nine times as low.

Explanation:

Sound intensity is defined as the acoustic power transferred by a sound wave per unit of normal area to the direction of propagation:

$I\propto \frac{1}{A}$

Since the sound wave has a spherical wavefront of radius r, then the area is given by:

$A=4\pi r^2$

Here r is the distance from the source of the sound. Thus sound intensity decreases as:

$I\propto \frac{1}{4\pi r^2}\\\\I'\propto \frac{1}{4\pi r'^2}\\\\I'\propto \frac{1}{4\pi (3r)^2}\\\\I'\propto \frac{1}{9} \frac{1}{4\pi r^2}\\\\I'\propto \frac{1}{9} I$

6 0

3 years ago

A pendulum bob executing simple harmonic motion has 2cm and 12Hz as amplitude and frequency respectively. Calculate the period o

Jobisdone [24]

Answer:

Explanation:

The amplitude is extraneous information for this question.

Period (T) is simply a measure of time (how long it takes to complete a full cycle).

The frequency (f), is the reciprocal (how many cycles it can complete per unit of time).

The frequency reported is 12Hz. Hz is a unit meaning "cycles per second"

Thus 12cycles = 1second.

To find the number of seconds per cycle, simply create the other unit fraction and simplify:

$T=\frac{1second}{12cycles}\\T=0.8\bar{3}\frac{seconds}{cycle}\\$

$T=0.83seconds$

7 0

1 year ago

Six members of a synchronized swim team wear earplugs to protect themselves against water pressure at depths, but they can still

tangare [24]

Answer:

The sound travels differently in different medium according the density of the medium.

Explanation:

The sound travels faster in dense medium and can be heard by the vibration of the bone present in the ear. The ear plugs reduce the sound intensity in both medium water and on land (air).

In air the sound is not heard properly due to the earplugs that stops the as the vibration are not able to produce as sound is not able to reach to middle ear, but Navy researchers have discovered that sound under water is heard by the bone present behind the ear, vibrations mastoid.

3 0

3 years ago

Sound level B in decibels is defined as

Lelechka [254]

Answer:

The approximate combined sound intensity is $I_{T}=1.1\times10^{-4}W/m^{2}$

Explanation:

The decibel scale intensity for busy traffic is 80 dB. so intensity will be

$10log(\frac{I_{1}}{I_{0}} )=80$ , therefore $I_{1}=1\times10^{8}I_{0}=1\times10^{8} * 1\times10^{-12}W/m^{2}=1\times10^{-4}W/m^{2}$

In the same way for the loud conversation having a decibel intensity of 70 dB.

$10log(\frac{I_{2}}{I_{0}} )=70$ , therefore $I_{2}=1\times10^{7}I_{0}=1\times10^{7} * 1\times10^{-12}W/m^{2}=1\times10^{-5}W/m^{2}$

Finally we add both of them $I_{T}=I_{1}+I_{2}=1\times10^{-4}W/m^{2}+1\times10^{-5}W/m^{2}=1.1\times10^{-4}W/m^{2}$ , is the approximate combined sound intensity.

3 0

3 years ago

What will an object weigh on the moon's surface if it weighs 190 n on earth's surface?

Greeley [361]

Turn your protracted to a 90 degree angle

3 0

3 years ago