A structural steel rod has a radius of 10 mm and a length of 1.0 m. A 100 KN force stretches it along its length. Calculate a stress, (b) elongation and (c) strain on the rod. Young's modulus of structural steel is2.0xx 10 ^(11) Nm^(-2).

A structural steel rod has a radius of 10 mm and a length of 1.0 m. A

1.	A structural steel rod has a radius of 10 mm and a length of 1.0 m. A 100 KN force stretches it along its length. Calculate a stress, (b) elongation and (c) strain on the rod. Young's modulus of structural steel is2.0xx 10 ^(11) Nm^(-2).
Answer» Solution :We assume that the ROD is held by a clamp at one end, and the force F is applied at the other end, parallel to the LENGTH of the rod. Then the stress on the rod is given by Stress `=(F)/(A)=(F)/(pir^(2))` `=(100xx10^(3)N)/(3.14xx(10^(-2)m)^(2))` `=3.18xx10^(8)" N m"^(-2)` The elongation, `Delta=((F//A)L)/(Y)` `=((3.18xx10^(8)" N m"^(-2))(1m))/(2xx10^(11)"N m"^(-2))` `=1.59xx10^(-3)` m `=1.59` mm The STRAIN is given by STR ain `=DeltaL//L` `(1.59xx10^(-3)m)//(1m)` `=1.59xx10^(-3)` `=0.16%`