Question

A force F is applied on a uniform rod of cross-section A and a force F’ is applied on a uniform rod of cross-section 3A. What is the relation between F and F’ if the pressure on both is the same?

(a) F/F’ = 1/3

(b) F/F’ = 3

(c) F’/F = 1/3

(d) F/F’ = 1/9

This question was addressed to me in quiz.

My doubt stems from Fluids Mechanical Properties Pressure topic in chapter Mechanical Properties of Fluids of Physics – Class 11

Answer 1

Correct choice is (a) F/F’ = 1/3

To explain: Pressure on first rod (P) = F/A

Pressure on the second rod (P’) = F’/3A

Given;

P = P’

F/A = F’/3A

F/F’ = 1/3.