<span>D) Electromagnetic radiation travels in the form of longitudinal waves.</span>
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.
Answer: Gravity. Since gravity is what holds the sun in place, earth and a whole generation plus galaxy, it makes gravity the strongest force of them all
Explanation:
1) the strong nuclear force, 2) the electromagnetic force, 3) the weak nuclear force, and 4) gravity
Answer:
Change in velocity and direction over a specific period of time.
Explanation:
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate the acceleration of an object.
Mathematically, acceleration is given by the equation;


Where,
a is acceleration measured in 
v and u is final and initial velocity respectively, measured in 
t is time measured in seconds.
Hence, the types of changes in motion that cause acceleration is a change in velocity and direction over a specific period of time.