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Novay_Z [31]
3 years ago
8

Who was the first known contributor to the atomic theory? Select one: a. Thomson b. Bohr c. Dalton d. Democritus

Physics
1 answer:
ser-zykov [4K]3 years ago
6 0
It would be D Democritus
He contributed in around 460-370 BC
Whereas the others contributed much later from around 1700's - 1900's
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Consider a river flowing toward a lake at an average velocity of 3 m/s at a rate of 500m3/sat a location 90 m above the lake sur
olga_2 [115]

Answer:

mechanical energy per unit mass is 887.4 J/kg

power generated is 443.7 MW

Explanation:

given data

average velocity = 3 m/s

rate = 500 m³/s

height h = 90 m

to find out

total mechanical energy and power generation potential

solution

we know that mechanical energy is sum of potential energy and kinetic energy

so

E = \frac{1}{2}×m×v² + m×g×h    .............1

and energy per mass unit is

E/m =  \frac{1}{2}×v² + g×h

put here value

E/m =  \frac{1}{2}×3² + 9.81×90

E/m = 887.4 J/kg

so mechanical energy per unit mass is 887.4 J/kg

and

power generated is express as

power generated = energy per unit mass ×rate×density

power generated = 887.4× 500× 1000

power generated = 443700000

so power generated is 443.7 MW

3 0
3 years ago
The Moon orbits Earth in an average of p = 27.3 days at an average distance of a =384,000 kilometers. Using Newton’s version of
Korvikt [17]

Answer:

The mass of the earth, M=6.023\times 10^{24}\ kg

Explanation:

It is given that,

Time taken by the moon to orbit the earth, T=27.3\ days=2358720\ m

Distance between moon and the earth,r=384000\ km=384\times 10^6\ m

We need to find the mass of the Earth using Kepler's third law of motion as :

T^2=\dfrac{4\pi^2}{GM}r^3

M=\dfrac{4\pi^2r^3}{T^2G}

M=\dfrac{4\pi^2\times (384\times 10^6)^3}{(2358720)^2\times 6.67\times 10^{-11}}

M=6.023\times 10^{24}\ kg

So, the mass of the earth is 6.023\times 10^{24}\ kg. Hence, this is the required solution.

7 0
3 years ago
When light passes through an object unchanged, scientists call that process _____.
Nataly [62]

<u>Answer</u>:

When light passes through an object unchanged, scientists call that process Transmission.

<u>Explanation</u>:

Transmission is the process where all the light that is passed through the material moves via the material without being absorbed. The Transmission depends on the affected radiation.The Transmittance of the medium is defined as the ratio between transmitted radiant power and incident radiant power. The light that is passed through the medium and not reflected will be either scattered or reflected. The light can be transmitted only through transparent or translucent material. Opaque object does not allows transmission of light.

5 0
3 years ago
A lamp consumes 1000J of ekectrical energy in 10s. Calculate its power.​
Mice21 [21]
You do 1000 divide it by 10 which equals 100 W
4 0
3 years ago
Yes or no
Tju [1.3M]

Answer:

1. No, it is a colloid

2. Yes

Explanation:

8 0
3 years ago
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