Question

If all the dimensions of a prismatic bar of square cross-section suspended freely from the ceiling of a roof are doubled then the total elongation produced by its own weight will increase

• A. eight times
• B. four times
• C. three times
• D. two times

Answer 1

The correct option is B four times

The area of bar will become 4 times, and the volume as well as weight will increase 8 times. So increase in elongation
$(\Delta =\frac{WL}{2EA})willbe$$\frac{8\times 2}{4}=4times$