Evidence of Energy Change Practice Test

A hockey puck is sliding on ice at 5 m/s. After several seconds, it slows down and stops (0 m/s). A student touches the puck and the ice right after it stops and notices both feel slightly warmer than before. A faint scraping sound was heard while it was sliding.

What conclusion do these observations best support about the energy changes?

A hockey puck slides across rough concrete. Its speed decreases from about 5 m/s to 0 m/s and it eventually stops. The student also hears a scraping sound, and the concrete feels slightly warmer near the path of the puck. What conclusion do these observations best support?