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Vaselesa [24]
3 years ago
10

What culture gave the visiting europeans eyeglasses and silk fabric

Physics
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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An 80-cm-long steel string with a linear density of 1.0 g/m is under 200 N tension. It is plucked and vibrates at its fundamenta
icang [17]

Answer:

Wavelength of the sound wave that reaches your ear is 1.15 m

Explanation:

The speed of the wave in string is

v=\sqrt{\frac{T}{\mu} }

where T= 200 N is tension in the string , \mu=1.0 g/m is the linear mass density

v=\sqrt{\frac{200}{1\times 10^{-3} }

v=447.2 m/s

Wavelength of the wave in the string is

\lambda =2L=2\times 0.8=1.6 m

The frequency is

f=\frac{v}{\lambda} \\f=\frac{447.2}{1.6}\\f=298.25 Hz

The required wavelength pf the sound wave that reaches the ear is( take velocity of air v=344 m/s)

\lambda=\frac{v_{air}}{f} \\\lambda=\frac{344}{298.25} \\\lambda=1.15 m

8 0
3 years ago
When a wave strikes a solid barrier it behaves like a basketball hitting a backboard this wave behavior years called?
Mama L [17]
This behavior is called reflection.
Reflection is a change of in direction of the wave when it reaches another medium. Imagine a wave colliding with a glass in a tank of water.
During reflection, some of the initial energy of the wave is lost.
Waves always reflect with at same angle at which it approached the obstacle.
5 0
3 years ago
If a man weighs 900 n on the earth, what would he weigh on jupiter, where the acceleration due to gravity is 25.9 m/s2?
balandron [24]
<span>So, if the man weight 900 newtons on Earth then that means, using F=ma, that the mass of the man is approximately 91.84 kg. This is because 900N=m(9.8m/s^2), and so it follows that 900/9.8=91.84. Using the man's found mass we then plug this into F=ma again. It follows that F=(91.84)(25.9)=2378.57N. This means that the man "weighs" 2378.57 Newtons on Jupiter, or about 2.5x as great as his weight on Earth. This makes sense, considering that 25.9/9.8 is approximately equal to 2.64.</span>
4 0
3 years ago
Electromagnetic waves have the ability to travel through empty space because they do not require a medium to travel through.
matrenka [14]

True. Electromagnetic energy does not require a medium.

7 0
3 years ago
Read 2 more answers
What is the differential equation governing the growth of current in the circuit as a function of time after t=0? express the ri
Reika [66]

Answer:

v_{b}=ir+L\frac{di}{dt}

Explanation:

A differential equation that contain a term with di(t)/dt is in a RL circuit. Here we have

v_{b}=v_{r}+v_{i}

where vr is the voltage in the resistance, vi is the voltage in the inductance and vb is the source voltage. But also we have that

v_{r}=ir\\v_{i}=L\frac{di}{dt}

where L is the inductance of the circuit, r is the resistance an i is the current. By replacing we have the differential equation

v_{b}=ir+L\frac{di}{dt}

I hope this is useful for you

regards

3 0
3 years ago
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