Answer:
The average velocity of the airplane for this trip is 1684.21 km/h
Explanation:
Average velocity is the rate of change of displacement with time. That is,
Average velocity =
= Δx / Δt = 
Now we will calculate the time taken by the airplane for the first motion before it encounters a wind.
From,
Velocity = 
Time = 
Therefore, Time = 
Time = 2.1h
This is the time taken before the airplane encounters a wind.
Hence, t1 = 2.1h
Now, For the time taken by the airplane when it encounters a wind
Also from,
Velocity = 
Time = 
Therefore, Time = 
Time = 1.625h
Hence, t2 = 1.625h
Now, to calculate the average velocity
Average velocity = 
x1= 2100, x2= 1300, t1= 2.1h and t2= 1.625h
Hence, Average velocity = 
Average velocity = 1684.21 km/h
Answer: Option (A) is the correct answer.
Explanation:
The process in which two or more small nuclei combine together to result in the formation of a larger nuclei is known as fusion.
In Sun, four hydrogen nuclei combine together to result in the formation of helium atom. This combining of small hydrogen nuclei to form a large helium nuclei represents fusion process occurring inside the Sun.
Thus, we can conclude that to power itself, the sun is constantly generating a nuclear reaction in its core, in which hydrogen nuclei are combined to form helium. This process is known as fusion.
B
A qualitative observation describes the characteristics of a substance without quantifying them.