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2 years ago

Please need help on this

Physics

1 answer:

kirill115 [55]2 years ago

8 0

The frequency cannot change, as it depends on the source. now, imagine light as a particle, when it's going through glass, which is a denser medium than air, is more tightly packed with particles than air is. think of it this way, will you walk faster in a crowd or on an empty street? going through the empty street (air) there are lesser objects to bump into so what do you think will happen to the speed now?

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An agriculturalist working with Australian pine trees wanted to investigate the relationship between the age and the height of t

SVETLANKA909090 [29]

Answer:

The correct answer is B.

Explanation:

Step 1:

The available regression equation is: Predict height= 0.29 + 0.48 (age).

Here, the predict height is dependent variable and the age is in-dependent variable.

Intercept = 0.29

Slope = 0.48

The given regression equation indicates the y on x model and the intercept coefficients of the regression equation is 0.29 and the slope is 0.48.

Step 2:

The height increases, an average, by 0.48 m per year.

Because co-efficient of slope variable indicate the positive sign and we increase 1 year in age then automatically height increased is 0.48 m.

<h3></h3><h3>The height increases, on average, by 0.48 meter each year.</h3>

6 0

3 years ago

A fan at a rock concert is 50.0 m from the stage, and at this point the sound intensity level is 114 dB. Sound is detected when

Marianna [84]

Answer:

A) $P=13.92\ J.s^{-1}$

B) $v=3730.9912\ m.s^{-1}$

C) $v=74.44\ mm.s^{-1}$

D) mosquitoes speed in part B is very much larger than that of part C.

Explanation:

Given:

Distance form the sound source, $s=50\ m$

sound intensity level at the given location, $\beta=114\ dB$

diameter of the eardrum membrane in humans, $d=8.4 \times 10^{-3}\ m$

We have the minimum detectable intensity to the human ears, $I_0=10^{-12}\ W.m^{-2}$

(A)

<u>Now the intensity of the sound at the given location is related mathematically as:</u>

$\beta=10\ log(\frac{I}{I_0} )$ ..........................................(1)

$114=10\ log\ (\frac{I}{10^{-12}} )$

$11.4=log\ I+12\ log\ 10$

$I=0.2512\ W.m^{-2}$

$I=\frac{P}{A}$

$0.2512=\frac{P}{\pi\times \frac{8.4^2}{4} }$

$P=13.92\ J.s^{-1}$ is the energy transferred to the eardrums per second.

(B)

mass of mosquito, $m=2\times 10^{-6}\ kg$

<u>Now the velocity of mosquito for the same kinetic energy:</u>

$KE=\frac{1}{2} m.v^2$

$13.92=\frac{1}{2}\times 2\times 10^{-6}\times v^2$

$v=3730.9912\ m.s^{-1}$

(C)

Given:

Sound intensity, $\beta = 20\ dB$

<u>Using eq. (1)</u>

$20=10\ log\ (\frac{I}{10^{-12}} )$

$2=log\ I+12\ log\ 10$

$I=10^{-10}\ W.m^{-2}$

Now, power:

$P=I.A$

$P=10^{-10}\times \pi\times \frac{8.4^2}{4}$

$P=5.54\times 10^{-9}\ J.s^{-1}$

Hence:

$KE=\frac{1}{2} m.v^2$

$5.54\times 10^{-9}=0.5\times 2\times 10^{-6}\times v^2$

$v=0.07444\ m.s^{-1}$

$v=74.44\ mm.s^{-1}$

(D)

mosquitoes speed in part B is very much larger than that of part C.

7 0

3 years ago

Is a computer an open or closed system

soldier1979 [14.2K]

Answer:

OPEN

Explanation:

7 0

2 years ago

Read 2 more answers

Most ocean waves obtain their energy and motion from _____. the wind the moon’s gravitational attraction the sun plate movement

Lelechka [254]

The correct answer is Tectonic plates

4 0

3 years ago

Read 2 more answers

If you jump off a 10 m diving platform, how long will it take you to hit the water?

Vilka [71]

Answer:

Option A is the correct option.

Solution,

S=10 m

u=0 m/s

a=9.8 m/s^2

Now,

<h3> $2s = a {t}^{2} \\ or \: {t}^{2} = \frac{2 \times 10}{9.8} \\ or \: {t}^{2} = \frac{20}{9.8} \\ or \: {t}^{2} = 2.04 \\ or \: t = \sqrt{2.04} \\ t = 1.43 \: seconds$ </h3>

hope this helps...

Good luck on your assignment...

8 0

3 years ago