🔍 Key Concepts

• Two-stroke vs four-stroke cycle: how many crankshaft revolutions per cycle • Power strokes per cycle: how often does each type of engine produce a power stroke • Relationship between number of power strokes and indicated horsepower when other factors are equal

💭 Think About

• Compare how many power strokes a two-stroke engine gets per crankshaft revolution versus a four-stroke engine • Think about what happens to power output if an engine can produce useful work every revolution instead of less often, assuming size and pressures are the same • Look carefully at which choice is describing horsepower and which are just describing the mechanical timing of strokes and revolutions

✅ Before You Answer

• Be clear on the definition of a cycle for 2-stroke and 4-stroke engines • Count the number of power strokes per crankshaft revolution for each engine type • Separate the idea of horsepower output from a simple description of motion (strokes and revolutions)