After a 15 minute wait on line, you finally are seated on the purple colored "Fuego" roller coaster cart right next to your best friend. As the roller coaster starts to roll, the wheels of the coaster slide against the track. This causes friction and little sparks appear under your seat. "Boy is that hot! Gotta love Takis!" you friend says. What kind of energy is formed between the wheels and track of the Taki roller coaster if heat is being produced? *