GATE Exam Questions - Engineering

Q1:

A vertical rod PQ of length L is fixed at its top end P and has a flange fixed to the bottom end Q. A weight W is dropped vertically from a height h(< L) on to the flange. The axial stress in the rod can be reduced by

A increasing the length of the rod

B decreasing the length of the rod

C decreasing the area of cross-section of the rod

D increasing the modulus of elasticity of the material

ANS:A - increasing the length of the rod

Stress is propotional to strain and (strain=PL/AE) thus reduction in length will decrease strain which will reduce stress.