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3 years ago

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Ancient Greek philosophers were the first to discuss atoms and matter. This became known in time as____________. Atomic theory s

tates that matter is composed of ____________ units called atoms.

1 answer:

Vedmedyk [2.9K]3 years ago

6 0

Answer:

atoms,

Explanation:

sorry don't know the second answer

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A student put her ear on one end of a long piece of lead. She asked her friend to

Ludmilka [50]

1) The length of the lead is 1700 m

2) The frequency of the wave is 400 Hz

Explanation:

1)

The wave in this problem is a sound wave, which is produced by the vibrations of the particles of air. It is a type of longitudinal wave (which means that the vibrations occur back-and-forth along the direction of propagation of the wave).

The speed of a sound wave in air is approximately

v = 340 m/s

In this problem, the sound wave is heard after a time of

t = 5 s

after the shot. Therefore, the distance travelled by the wave in this time (and therefore, the length of the lead) is

$d=vt=(340)(5)=1700 m$

2)

The frequency of a wave is the number of complete cycles made by the wave in one second.

For the wave in this problem, we are told that the wave has 2000 whole wavelengths in 5 seconds: this means that the wave completes 2000 cycles in 5 seconds. Therefore, we can find the frequency by setting up the following proportion:

$\frac{2000}{5}=\frac{x}{1}$

where x is the number of cycles made in 1 second. Solving for x,

$x=\frac{2000\cdot 1}{5}=400 s^{-1}$

Therefore, the frequency of the wave is

$f=400 Hz$

Learn more about waves and frequency:

brainly.com/question/5354733

brainly.com/question/9077368

#LearnwithBrainly

7 0

4 years ago

P waves and S waves are alike in that they __________.

sammy [17]

<h3><u>Answer;</u></h3>

travel through solids

P waves and S waves are alike in that they<u> both travel through solids</u>.

<h3><u>Explanation;</u></h3>

<em><u>P-waves and S-waves are types of seismic waves.</u></em> These waves are produced during an earthquake, that transmit energy released around the earth.
<u><em>P-waves travel the fastest and also travel through solids, liquids and gases. </em></u>They are push and pull waves and thus they cause rock particles to move back and forth.
<u><em>S-wave son the other hand arrive at a given point after the p-waves. They do not travel as fast as P-waves. They travel through solids but not in liquids and gases.</em></u> S -waves cause the rocks to move side to side.

3 0

3 years ago

Read 2 more answers

Water flows through a water hose at a rate of Q1 = 860 cm3/s, the diameter of the hose is d1 = 1.85 cm. A nozzle is attached to

Snowcat [4.5K]

Answer:

a) A1 = $\frac{\pi (d1)^{2} }{4}$

b) A1 = 2.688 cm $^{2}$

c) Q1 = A1 x v1

d) v1 = 3.1994 m/s

e) A2 = $\frac{A1 X v1}{v2}$

f) A2 = 0.7963cm $^{2}$

Explanation:

a) Area = $\pi r^{2}$

r = $\frac{d}{2}$

thus,

area = $\pi (\frac{d}{2})^{2}$

A1 = $\frac{\pi (d1)^{2} }{4}[/tex]b) d1 = 1.85 cmsubstituting in the above equation,A1 = [tex]\frac{\pi (d1)^{2} }{4}$

A1 = $\frac{\pi (1.85)^{2} }{4}$

A1 = 2.688 cm $^{2}$

c) Flow rate = Area x velocity ( refer brainly.com/question/13997998)

Q1 = A1 x v1

d) From the above equation,

v1 = $\frac{Q1}{A1}$ = $\frac{860}{2.688}$ = 319.94 cm/s = 3.1994 m/s

e) Since the flow rate Q1 is constant throughout the hose, Av is a constant.

i.e. A1 x v1 = A2 x v2

thus,

A2 = $\frac{A1 X v1}{v2}$

f) v2 = 10.8 m/s.

substituting the values in the above equation,

A2 = $\frac{2.688 X 3.1994}{10.8}$ = 0.7963cm $^{2}$

3 0

4 years ago

Which type of coolant(s) usually is (are) used to remove heat from a nuclear reactor core?

Ilya [14]

Answer:

(B). Liquid sodium or water

Explanation:

I don't know how to explain this But hope it right!

If I'm wrong I'm sorry

If I'm right Thank you and (brainliest plz)

6 0

3 years ago

A car’s bumper is designed to withstand a 4.0-km/h (1.1-m/s) collision with an immovable object without damage to the body of th

poizon [28]

Answer:

The force bumper at 0.200m

F=2722.5 N

Explanation:

Using the energy theorem of work

$W=K_{f}- K_{i}$

W=ΔK

W=F*d

ΔK= $\frac{1}{2}*m*v_{f} ^{2} -\frac{1}{2}*m*v_{i} ^{2}$

$v_{i} =0$

ΔK=F*d= $\frac{1}{2}*m*v_{f} ^{2} -\frac{1}{2}*m*v_{i} ^{2}$

$F*d=\frac{1}{2}*m*0 ^{2}- \frac{1}{2}*m*v_{i} ^{2}\\F*d=-\frac{1}{2}*m*v_{i} ^{2}=\frac{1}{2}*900kg*(1.1\frac{m}{s})^{2}\\F*d=544.5\frac{kg*m}{s^{2}}\\ F=\frac{544.5\frac{kg*m}{s^{2}}}{0.2m} \\F=2722.5 N$

3 0

3 years ago