Answer:
D.
For every action there is an equal and opposite reaction.
Explanation:
im doing the same one lol
Because the gravity near the earths crust/surface is greater than once in orbit it doesnt need any fuel because the earths gravatitional pul is keeping it in orbit just like it keeps the moon it orbit around it and the sun keeps the planets in its orbit
Hope This Helps!
The total distance covered by the person is 12 times the height of each stair:

The work done by the person to climb the stairs is equal to the increase in his gravitational potential energy:

And therefore, the power generated by the person in 12 s is the work done divided by the time taken:

So, the correct answer is B.
Answer:
a 
b
Explanation:
Generally the force constant is mathematically represented as

substituting values given in the question
=> 
=> 
Generally the workdone in stretching the spring 3.5 m is mathematically represented as

=> 
=> 
Generally the workdone in compressing the spring 2.5 m is mathematically represented as
=>
=>