Answer:
12500W
Explanation:
Given parameters:
Work done = 250000J
Time taken = 20s
Unknown:
Power of the crane = ?
Solution:
Power is the defined as the rate at which work is being done;
Mathematically;
Power = 
insert the parameters and solve;
Power = 
= 12500W
Answer:
Light with a wavelength of 100 nm is completely absorbed by the atmosphere. True
Light with a wavelength of 400 nm has the color of red. False
Light with a wavelength of 280 nm is in the ultraviolet region. False
Explanation:
Light of wavelength 0-100nm can be absorbed by the earths atmosphere
Ultraviolet light ranges between 320-400nm hence the statement above is false.
The wavelength of red colour is around 620-700nm hence the statement above is false.
False because they let it in to the atmosphere and then its condenced
Answer:
Option (3)
Explanation:
According to researches done by the astronomers, it has been found that the earth collided with a giant Mars-size early proto-planet, whose name was 'Theia' during the Hadean era, about.5 billion years back. This collision resulted in the detachment of a considerably huge amount of material away from the earth. The remnant debris particles accumulated and gave rise to the formation of moon. The earth during that time was comprised of molten lava only, and from this collision, the earth attained its tilt of approximately 23.5°.
Thus, the correct answer is option (3).
If you know the distance that an object travels in one unit of time, you can determine the velocity at which it was initially projected.
