The minimum velocity the roller-coaster need when going over the 12 m to make it to the top of the 30 m hill is equal to 18.78 m/s. Therefore, option (D) is correct.
<h3>What is the law of conservation of energy?</h3>
Energy can be transformed from one to another but can neither be created nor destroyed. Energy is present in nature in several forms such as heat, nuclear energy, electricity, chemical energy, and so on.
If every form of energy is considered, then the total energy of an isolated system remains constant. This law of energy applies to all types of energy in our universe.
From the law of conservation of energy, the energy of the roller-coaster goes:
Given the height of the first hill, h₁ = 12m
The height of the second hill, h₂ = 30 m
The gravitational acceleration, g = 9.8 m/s²
We can find the value of the minimum velocity of the roller-coaster from the above equation:
0.5 × v² + (9.8) × 12 = (9.8) × 30
0.5 v² = 176.6
v = 18.78 m/s
Learn more about the law of conservation of energy, here:
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