PHYS 1003 Lecture 2: PHYS1001H- Exam Review
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It allows you to predict will (or won"t(cid:524) move: newton knew about energy, nut it wasn"t considered important in his time. )t became important in the (cid:857)(cid:864)(cid:856)(cid:856)"s when steam engines were being invented. Then the question was: how much useful work can i get out of an engine, notion of (cid:498)useful work(cid:499) led to the idea of (cid:498)horsepower(cid:499), which is work /second, energy is the potential to do work. Gasoline stores 45 mj of energy per liter. An active adult male consumes 2500 kcal of energy per day. The average canadian home consumes 1000 kw-hours of energy per month: power is the work done (or energy consumed) per second. Most small cars have 150 hp engines (1 hp = 746 j/s), which means that they can consume up to 112 kj/s of energy. At that rate, you"d burn through (cid:857) liter of gasoline in (cid:860)(cid:856)(cid:856) s, or (cid:862). (cid:863) minutes.
