The correct answer should be C. Hydroelectric power stations can only produce enough energy for a small town as they do not produce large quantities
Hydroelectric power stations can power even large cities that have millions of people.
Answer:
From the formula of force:

since AB and k are constants:

x is a constant of proportionality
• when force is 4N, separation distance is 1

therefore, equation becomes

when r is doubled, r becomes 2. find F:

Answer:
By conservation of energy, it can climb up to a height equal to that it went down before. However, due to the friction in the machines, the total mechanical energy of the roller coaster will decrease. As a result, the first "hill" of many roller coasters are the highest, but the followings will have decreasing heights.
Explanation: