To solve this problem it is necessary to apply the concepts related to gravity as an expression of a celestial body, as well as the use of concepts such as centripetal acceleration, angular velocity and period.
PART A) The expression to find the acceleration of the earth due to the gravity of another celestial body as the Moon is given by the equation

Where,
G = Gravitational Universal Constant
d = Distance
M = Mass
Radius earth center of mass
PART B) Using the same expression previously defined we can find the acceleration of the moon on the earth like this,



PART C) Centripetal acceleration can be found throughout the period and angular velocity, that is

At the same time we have that centripetal acceleration is given as

Replacing



Hooke's Law states that the extension is directly proportional to the force applied so:
F/x = constant
F₁/x₁ = F₂/x₂
2 / 0.02 = 1600 / x₂
x₂ = 16 m
Elastic work = 1/2 Fx
= 1/2 * 1600 * 16
= 12.8 kJ
Answer:

Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:

and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:

From basic physics we know:

so:


Using the previous information in equation (1)

Factoring:
(2)
Finally, replacing the data in (2)

Answer:
Fossil-fueled cars are still outnumbering the alternative and replacement-fueled cars because they are generally cost-effective and are efficient.
Explanation:
<em>Fossil fuels</em> are non-renewable energy that cannot be replenished. Although many people know how harmful using them can be to the environment, still, people continue to buy cars that are powered by it. This is because, <em>using fossil-fueled cars can help you save money</em> compared to using<em> replacement-fueled cars.</em><em> Its engines are also more powerful,</em> which means they can arrive at their destination in just a few minutes. <u>This makes it efficient.</u> The cost of maintaining a fossil-fueled car is less expensive compared to<em> replacement-fueled cars.</em> People are naturally keen when it comes to budgeting, thus, many people still buy cars powered by fossil fuels.