Question

In water transportation of timber, the arms of V shaped boom incline at an angle of _________.

• A. $20^\circ$
• B. $30^\circ$
• C. $40^\circ$
• D. $50^\circ$

Hint:

In structural design and fluid dynamics, the trigonometric values of $30^\circ$ (where $\sin 30^\circ = 0.5$) provide a balanced distribution of tensile and compressive loads, making it a standard structural angle for riverine boom arrays.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Water transportation of timber, including drifting and floating of logs along rivers, is an economical transport method in mountainous forest regions.
Booms are floating structures designed to guide, collect, or arrest floating timber logs at designated storage or processing sites along a river bank.

Step 2: Detailed Explanation:
A V-shaped boom consists of two buoyant arms joined together to form a wedge shape pointing upstream.
The angle of inclination of these arms relative to the central axis or current of the watercourse is mathematically critical:
- If the angle is too large, the boom acts as a major barrier, facing extreme hydraulic force from the current, which can cause structural failure or allow logs to spill over.
- If the angle is too small, the entrance width is reduced, lowering the efficiency of capturing drifted logs.
According to hydraulic principles in forest engineering, an inclination angle of $30^\circ$ balances the mechanical forces acting on the boom while maximizing log capture efficiency.

Step 3: Final Answer:
The arms of a V-shaped boom are inclined at an angle of $30^\circ$, corresponding to option (B).