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3 years ago

What culture gave the visiting europeans eyeglasses and silk fabric

1 answer:

kondor19780726 [428]3 years ago

7 0

The culture that gave the visiting Europeans eyeglasses and silk fabric was the Chinese civilization. The Chinese invented eyeglasses over a 1,000 years ago<span>, according to British scientist and historian Sir Joseph Needman. By the time Marco Polo arrived in China around 1270, eyeglasses (which he mentions in his accounts) were widely used in Chinese upper class. On the other hand, s</span>ilk has been used by the Chinese for approximately 5,000 years.<span> The earliest evidence of silk dates back to around 4,000-3,000 BC in Shanxi province, where a culture silk cocoon was found.</span>

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what is the desnity of a material that has 2500 grams and a volume of 500 cubic centimeters in grams per cubic centimeter

Ann [662]

Divide 2500 g by 500 cc. The quotient is 5 g/cc ... the density.

4 0

4 years ago

2. A common physics experiment involves lowering an open tube into a cylinder of water and moving the tube up and down to adjust

notsponge [240]

Answer:

Explanation:

This question pertains to resonance in air column. It is the case of closed air column in which fundamental note is formed at a length which is as follows

l = λ / 4 where l is length of tube and λ is wave length.

here l = .26 m

λ = .26 x 4 = 1.04 m

frequency of sound = 330 Hz

velocity of sound = frequency x wave length

= 330 x 1.04

= 343.2 m /s

b )

Next overtone will be produced at 3 times the length

so next length of air column = 3 x 26

= 78 cm

c )

If frequency of sound = 256 Hz

wavelength = velocity / frequency

= 343.2 / 256

= 1.34 m

= 134 cm

length of air column for resonance

= wavelength / 4

134/4

= 33.5 cm

7 0

3 years ago

A bat strikes a 0.145-kg baseball. Just before impact, the ball is traveling horizontally to the right at 43.0 m/s; when it leav

kotykmax [81]

Answer:

$-7.352\times 10^3$ N

Explanation:

We are given that

Mass of baseball=m=0.145 kg

Initial velocity of ball=u=43 m/s

$\theta=31^{\circ}$

Speed, v= $51 m/s$

Time, t=1.71 ms= $1.71\times 10^{-3} s$

$1 ms=1.71\times 10^{-3} s$

Horizontal component of the average force on the ball= $\frac{m(vcos\theta-u)}{t}$

Horizontal component of the average force on the ball $=\frac{0.145(-51cos31-43)}{1.71\times 10^{-3}}$

Horizontal component of the average force on the ball= $-7.352\times 10^3$ N

6 0

4 years ago

A bag of cement has a mass of 62 g. What is the mass of the bag of cement in S.I. units (kg)?

NNADVOKAT [17]

The mass of this bag of cement in S.I. units (kg) is equal to 0.062 kilograms.

<u>Given the following data:</u>

Mass of cement = 62 grams.

To calculate the mass of this bag of cement in S.I. units (kg):

<h3>How to convert to S.I. units.</h3>

In Science, kilograms (kg) is the standard unit of measurement or S.I. units of the mass of a physical object. Thus, we would convert the value of the mass of this bag of cement in grams to kilograms (kg) as follows:

<u>Conversion:</u>

1000 grams = 1 kilograms.

62 grams = X kilograms.

Cross-multiplying, we have:

X = $\frac{62}{1000}$

X = 0.062 kilograms.

Read more on mass here: brainly.com/question/13833323

8 0

2 years ago

If you are driving an oscillatory system at a certain frequency, but the amplitude is much smaller than it could be, you can be

kakasveta [241]

Answer:

3. The driving frequency is not matched to the natural frequency of the oscillatory system.

Explanation:

It is the condition of resonance when the one body that oscillates with a maximum amplitude when the frequency of the applied force is equal to the natural frequency of the body.

Every body has its own natural frequency.

Here the driving force may be more or less but we are sure that it is not equal to the natural frequency of oscillatory system. Hence the force is not in resonance with the oscillatory system.

5 0

3 years ago