8x^3/27y^8×9y^3/12x^2

If f = 136 lb , determine the resultant couple moment.

olga_2 [115]

136lb?? I'm so confused rn!! I'm super sorry!!

8 0

4 years ago

To understand the decibel scale. The decibel scale is a logarithmic scale for measuring the sound intensity level. Because the d

frez [133]

The question is incomplete. Here is the complete question.

To understand the decibel scale. The decibel scale is a logarithmic scale for measuring the sound intensity level. Because the decibel scale is logarithmic, it changes by an additive constant when the intensity when the intensity as measured in W/m² changes by a multiplicative factor. The number of decibels increase by 10 for a factor of 10 increase in intensity. The general formula for the sound intensity level, in decibels, corresponding to intensity I is

$\beta=10log(\frac{I}{I_{0}} )dB$ ,

where $I_{0}$ is a reference intensity. for sound waves, $I_{0}$ is taken to be $10^{-12} W/m^{2}$ . Note that log refers to the logarithm to the base 10.

Part A: What is the sound intensity level β, in decibels, of a sound wave whose intensity is 10 times the reference intensity, i.e. $I=10I_{0}$ ? Express the sound intensity numerically to the nearest integer.

Part B: What is the sound intensity level β, in decibels, of a sound wave whose intensity is 100 times the reference intensity, i.e. $I=100I_{0}$ ? Express the sound intensity numerically to the nearest integer.

Part C: Calculate the change in decibels ( $\Delta \beta_{2},\Delta \beta_{4}$ and $\Delta \beta_{8}$ ) corresponding to f = 2, f = 4 and f = 8. Give your answer, separated by commas, to the nearest integer -- this will give an accuracy of 20%, which is good enough for sound.

Answer and Explanation: Using the formula for sound intensity level:

A) $I=10I_{0}$

$\beta=10log(\frac{10I_{0}}{I_{0}} )$

$\beta=10log(10 )$

β = 10

The sound Intensity level with intensity 10x is 10dB.

B) $I=100I_{0}$

$\beta=10log(\frac{100I_{0}}{I_{0}} )$

$\beta=10log(100)$

β = 20

With intensity 100x, level is 20dB.

C) To calculate the change, take the f to be the factor of increase:

For $\Delta \beta_{2}$ :

$I=2I_{0}$

$\beta=10log(\frac{2I_{0}}{I_{0}} )$

$\beta=10log(2)$

β = 3

For $\Delta \beta_{4}$ :

$I=4I_{0}$

$\beta=10log(\frac{4I_{0}}{I_{0}} )$

$\beta=10log(4)$

β = 6

For $\Delta \beta_{8}$ :

$I=8I_{0}$

$\beta=10log(\frac{8I_{0}}{I_{0}} )$

β = 9

Change is

$\Delta \beta_{2},\Delta \beta_{4}$ , $\Delta \beta_{8}$ = 3,6,9 dB

6 0

3 years ago

Hydrogen/hydronium ion concentration

Valentin [98]

Answer:

Pure water is considered to neutral and the hydronium ion concentration is 1.0 x 10-7 mol/L which is equal to the hydroxide ion concentration. So the pH is the -log of the [hydronium ion].

Explanation:

Pure water is considered to neutral and the hydronium ion concentration is 1.0 x 10-7 mol/L which is equal to the hydroxide ion concentration. So the pH is the -log of the [hydronium ion].

5 0

4 years ago

What property of matter determines the electrical conductivity of a substance?

vlada-n [284]

"Valence" electrons or the free electrons

Explanation:

Electrical conductivity can be defined as the property of the substance to conduct electricity, heat etc through it. This conductivity is caused due to the migration of particles which are electrically charged within the atomic lattice of the substance.

The outermost electrons or the electrons in valence shell are the main cause behind the conductivity property exhibited by any substance. Higher the number of electrons in outer shell, higher the conductivity.

Since these electrons are in the outermost shell, they can move easily. Under an impact of applied heat, charge these electrons migrate through the atomic lattice and thus conducts electricity, heat as the case may be.

4 0

3 years ago

Two people are pushing a couch from the same side. One person pushes with a force of 2 N. The other person pushes with a force o

SashulF [63]

Answer:

the answer is letter d because both of them are pushing the couch in the same direction so 4 plus 2 will give you 6N

8 0

3 years ago