Agasoline engine with efficiency 25% delivers 1500 j of mechanical work per cycle. how much heat does this engine discard per cycle? (a) 6000 (b) 7500j (c) 4500j (d) 375 (e) 2000

(C) 4500J

Explanation:

η = Efficiency of the gasoline engine = 25% = 0.25

W = mechanical work done by engine per cycle = 1500 J

E = Total input heat

mechanical work done by engine per cycle is given as

W = η E

1500 = (0.25) E

E = 6000 J

U = heat discarded by the engine per cycle is given as

U = E - W

U = 6000 - 1500

U = 4500 J

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it