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3 years ago

Show that atmosphere exerts pressure.

1 answer:

3 0

Because gas particles in the air like particles of all fluids are constantly moving and bumping into things, they exert pressure. The pressure exerted by the air in the atmosphere is greater close to Earth's surface and decreases as you go higher above the surface.

<u>Explanation</u>:

Fill roughly one-third of a cup with water. Then, cover the mouth of the cup completely with a flat, hard cardboard. Using your hand to keep it in place, turn the cup upside down. When you remove your hand, the the cardboard stays in place.

One would expect that due to gravity, the water will fall, and even the cardboard will. However, it does not, which means that something must be applying an upward force on the cardboard. This is nothing other than air pressure, which applies a force across the surface of the cardboard in an upward direction.

Thus we can demonstrate that air exerts pressure, because otherwise, the water would have fallen.

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Define thermal conductivity.

ladessa [460]

Answer:

A measure of the ability of a material to transfer heat.

Explanation:

Please mark me as brainliest please

4 0

3 years ago

Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.39~\mathrm{W/m^2}1.39 W/m 2 . If a rada

wolverine [178]

Answer:

0.763 m

Explanation:

Intensity I = power P ÷ area A of exposure (spherical area of propagation)

I = P/A

A = P/I

Power = 10.0 W

Intensity = 1.39 W/m^2

A = 10/1.39 = 7.19 m^2

Area A = 4¶r^2

7.19 = 4 x 3.142 x r^2

7.19 = 12.568r^2

r^2 = 7.19/12.568 = 0.57

r = 0.753 m

3 0

3 years ago

One small speaker is placed 3m to the east of a second speaker, and a listener stands 4m directly south of one of the speakers.

alexandr402 [8]

Answer:

The value is $\lambda = 2 \ m$

Explanation:

From the question we are told that

The distance of the speaker from the second speaker to the east is $d = 3 \ m$

The distance of the speaker from the listener to the south is $a = 4 \ m$

Generally given that if the speaker move in any direction, their sound become louder , it then mean that the position of the listener of minimum sound (i.e a position of minima ) ,

Generally the path difference of the sound produce by both speaker at a position of minima is mathematically represented as

$y = \frac{\lambda}{2}$

Generally considering the orientation of the speakers and applying Pythagoras theorem we see that distance from the second speaker to the listener is mathematically represented as

$b = \sqrt{d^ 2 + a^2 }$

=> $b = \sqrt{3^ 2 + 4^2 }$

=> $b = 5$

Generally the path difference between the two speaker with respect to the listener is

$y = b - a$

=> $y = 5 - 4$

=> $y = 1$

$1 = \frac{\lambda}{2}$

=> $\lambda = 2 \ m$

4 0

3 years ago

The chart below represents the steps in the process of a bill becoming a law. Use the chart to answer the following question.

NARA [144]

H would be the correct answer senate house of rep then congress then president to sign

8 0

4 years ago

Read 2 more answers

What waves need molecules in order to transfer energy

nevsk [136]

Answer:

Mechanical waves

Explanation:

Waves are periodic oscillations, that carry energy, but not matter.

Waves are classified into two types:

- Mechanical waves: these waves are produced by the oscillations of the particles in a medium, which can oscillate along the direction of propagation of the wave (longitudinal wave) or perpendicular to the direction of motion of the wave (transverse wave). These waves can only propagate in a medium, so they cannot travel in a vacuum. Examples of mechanical waves are sound waves.

- Electromagnetic waves: these waves are produced by the oscillations of electric and magnetic field. They are transverse waves. They are the only type of wave able to propagate through a vacuum (so, through space).

Therefore, the waves that need molecules in order to transfer energy are mechanical waves.

4 0

3 years ago