Difficulty: Easy
Correct Answer: 40/ √3 m
Explanation:
Introduction / Context:
The wire forms the hypotenuse of a right triangle with the ground (adjacent) and the pole (opposite). The angle given is with the horizontal, so use sine to relate opposite and hypotenuse.
Given Data / Assumptions:
Concept / Approach:
sin θ = opposite / hypotenuse → hypotenuse = opposite / sin θ.
Step-by-Step Solution:
Verification / Alternative check:
Numeric: √3 ≈ 1.732 → L ≈ 23.094 m; geometry consistent with a steep wire.
Why Other Options Are Wrong:
40√3 is too long (would imply sin 60° < 0.5); 20√3 and 20/√3 arise from mixing cosine or tangent incorrectly.
Common Pitfalls:
Using cos instead of sin since angle is with ground; rationalizing incorrectly; forgetting the 1/2 factor in sin 60°.
Final Answer:
40/ √3 m
Discussion & Comments