# When a car is braked to a stop, its kinetic energy is transformed to?

a) stopping energy.

b) potential energy.

c) energy of motion.

d) energy of rest.

e) heat.

• e) Heat energy,

The break pads rub against the wheels causing friction which generates heat (similar so rubbing sandpaper generates heat). There will also be some energy lost as sound (the screech of breaks).

The two people who said potential energy are just wrong, if something was dropped from a height then its potential energy would start high and then fall as it was converted into kinetic energy.

• The correct answer is potential energy, because as you kinetic enerygy increases ( the car gaining speed) your potential energy decreases, and as your kinetic energy decreases ieeg, braking your kinetic energy is transformed into potential energy, because of the law of conservation of energy, you cannot lose evergy so that kinetic is transprned into potential energy ANS B

• potential

If the car braking system involved driving into the ocean there would be no need to discuss heat and

potential energy would still be the right answer.

• e) is the answer. the brakes heat up

• Heat, which is ultimately radiated into space.

• e) heat enegy.