What best demonstrates the transformation of mechanical energy to heat energy and light energy?

The movement of electrons demonstrate the best conversion of mechanical into heat energy and light energy .

electrons travels with a velocity so it clearly indicates mechanical energy

while travelling it releases heat energy(dissipation) .In lamps heat energy makes to glow the lamps (which converts heat energy to light energy).

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.