Please show work and answer with correct units. Thank you. A four-cylinder gasol

Question

Please show work and answer with correct units. Thank you.

A four-cylinder gasoline engine has an efficiency of 28% and delivers 280J of work per cycle per cylinder.

Part A:

If the engine runs at 25 cycles per second (1500 rpm), determine the work done per second.

Express your answer to two significant figures and include the appropriate units.

Part B:

What is the total heat input per second from the gasoline.

Express your answer to two significant figures and include the appropriate units.

Part C:

If the energy content of gasoline is 130 MJ per gallon, how long does one gallon last?

Express your answer to two significant figures and include the appropriate units.

Part B:

Explanation / Answer

1) Engine fires at 25 cycles/s:

280 J / cycle/ cylinder * 4 cylinders * 25 cycles/second = 28000 J/s
Work = 28000 Joules every second
--------------------------------------...
2) Total heat equals:

28000 J = 28% efficiency so "X" many Joules equals 100% effiicency?
28% / 100% = 28000 / X
solve for X :
X = 100000 Joules of heat per second
--------------------------------------...

3) 130MJ = 130,000,000 Joules

the engine uses 100000 Joules of heat every second so:

130,000,000 J / 100000J = 1300 seconds of running time or about 21.667 minutes

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