Please answer and explain! ### Roller Coaster Physics Problem**Problem Statement:**A roller coaster starts from rest at the top of an 18-meter hill, as shown in the diagram. The car travels to the bottom of the hill and continues up the next hill that is 10.0 meters high.**Question:**How fast is the car moving at the top of the 10.0-meter hill, if friction is ignored?**Options:**A) 6.4 m/s B) 8.1 m/s C) 13 m/s D) 18 m/s E) 27 m/s **Diagram Explanation:**- The diagram depicts a roller coaster track with an initial drop from a height of 18 meters, followed by a rise to a secondary hill with a height of 10 meters.- The beginning of the track, where the car is at rest, is clearly marked at the 18-meter point.- The second hill is indicated to be 10 meters high, and the track gradually ascends to this height from ground level.

We are given a roller coaster. We ignore friction here. Since there is no friction, the mechanical energy is conserved. This means that potential energy at start which be converted to potential and kinetic energy at the next hill. We can hence find the speed of car.Height of first hill H=18m Height of 2nd hill h=10m The change in gravitational potential energy of car at 2 hills is converted to its kinetic energy at 2nd hill. Let the mass of car be m. Hence, KE=∆PE12mv2=mgH-h12v2=gH-hv2=2gH-hv2=2×9.8×18-10v2=156.8v=12.53v≈13 m/s Hence Option C) is correct.

Answered: 4. A roller coaster starts from rest at…