The acceleration due to gravity serves as the centripetal acceleration of the objects that orbits the Earth. The centripetal acceleration due to gravity is calculated through the equation,
a = v²/r
where v is the speed and r is the radius. Substituting the known values to the equation,
9.8 m/s² = (420 m/s)² / r
The value of r from the equation is 18000 m or equal to 18 km.
<em>Answer: 18 km</em>
I believe the correct answer from the choices listed above is option C. X-rays have greater frequency than microwaves. In a electromagnetic spectrum, the order in increasing frequency is as follows:
radio waves,microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation,X-rays<span> and gamma </span>rays<span>.</span>
So the best conductor for electricity is silver.
However because silver is so expensive we use copper which is the next best conductor
Answer:
<u>Development in science:</u>
There a number of individuals in the world around us who has improved the field of science and made it easy for us to know this universe more easily then ever. This universe is still unexplored and there are going to be more then billions of stars which are still not studied and has an immense amount of information regarding the universe.
<u>Stephen Hawking:</u> The scientist who made it easy for each of us to know the universe and more over the cosmos in a more detailed form, as before this no one knew about the different patterns of entities and there properties.
<u>A genius who was handicapped:</u>
He was a genius in cosmology, mathematics, and other subjects of science as he was diagnosed by the amyotrophic lateral sclerosis(ALS), which made it unable for him to live a normal life.But, he communicated through a computer which detected his nerve signals and shared his thoughts about any thing or subject.
<u>Why him?</u>
Stephen hawking was just tremendous in making it more understandable about the black holes, time worms, and space etc.As it was known to very small number of people before he took the stage.
