Broken collarbones broken spines
Do roller coaster have engines?
No, they are not powered (they need chains or launchers to get up the first hill) and therefore, they do not have engines.
What does it mean by a roller-coaster ride as an idiom?
If you think about this, you can figure it out. A roller coaster is a fast, scary ride. If something is like a roller coaster ride, it would be a very busy experience that is fun, but also slightly scary.
How much mechanical energy is at the top of a roller coaster?
It depends on the roller coaster's height,speed,and location. :p