BASICS OF UNITS — Choose the correct equivalence. Question: One horsepower (hp) is equal to how many watts (W)?

Introduction / Context:
Horsepower is a traditional unit of power still seen in automotive specifications. In SI, power is measured in watts. Converting horsepower to watts is a standard recall item bridging legacy and SI systems.

Given Data / Assumptions:

• We are using the mechanical horsepower defined by James Watt for engines.
• SI base unit of power is the watt (W).
• No alternate metric horsepower is implied unless stated.

Concept / Approach:
Mechanical horsepower is defined exactly as 550 foot-pounds per second. Converting foot-pounds to joules and seconds gives a fixed value in watts. The widely standardized conversion is 1 hp = 745.7 W, rounded to 746 W for most exam purposes.

Step-by-Step Solution:
Start with definition: 1 hp = 550 ftlbf/s.1 ftlbf ≈ 1.3558179 J.So power = 550 * 1.3558179 J/s ≈ 746 W.Rounded value used in textbooks: 746 watts.

Verification / Alternative check:
Automotive conversions often use hp to kW: 1 kW ≈ 1.341 hp, hence 1 hp ≈ 0.7457 kW = 745.7 W → 746 W rounded.

Why Other Options Are Wrong:
B) 748 W — too high; not the accepted rounded value.C) 756 W — off by more than 1%.D) 736 W — close to metric horsepower (PS) confusion; mechanical hp is ≈ 745.7 W, metric horsepower is ≈ 735.5 W.E) 700 W — rough and incorrect.

Common Pitfalls:
Mixing mechanical horsepower with metric horsepower (PS). Always check which definition the question uses; standard school exams use 746 W.

Final Answer:
746 watts