Question

Which assumption states that a plane section remains plane before and after bending?

• A. Hooke's Law
• B. Bernoulli's assumption
• C. Pascal's Law
• D. Newton's Law

Hint:

Remember: Bending theory → Plane sections remain plane (Bernoulli).

Answer 1

The Correct Option is B

Concept: In the theory of bending, certain assumptions are made to simplify analysis of beams.
Step 1: Understanding the assumption.
It states that cross-sections of a beam that are plane before bending remain plane after bending.
Step 2: Name of the assumption.
This is known as Bernoulli's assumption.
Step 3: Importance.
It helps in deriving the bending equation and analyzing stress distribution.
Step 4: Evaluating the options.

• Hooke's Law $\rightarrow$ Stress-strain relation (incorrect)
• Bernoulli's assumption $\rightarrow$ Plane sections remain plane (correct)
• Pascal's Law $\rightarrow$ Fluid pressure law (incorrect)
• Newton's Law $\rightarrow$ Laws of motion (incorrect)

Step 5: Conclusion.
Thus, the assumption is Bernoulli's assumption.