4. A steel rod 20 m long is at temperature of 20C. If temperature is raised by 60C, then the free expansion of length in mm will be (Assume thermal stress coefficient, = 12x10-6 / C)(2 pts)

5. A weight falls on a collar rigidly attached to the lower end of a vertical bar 5 m long and 800 mm2 in section. If the maximum instantaneous extension is 2 mm, then stress in the bar in MPa will be (E = 200 GPa) (2 pts)

4. A steel rod 20 m long is at temperature of 20C. If temperature is raised by 60C, then the free expansion of length in mm will be (Assume thermal stress coefficient, a = 12x10-%C) (2 pts) (a) 9.6 mm () ) (b) 9.6x10-3 mm ( ) (c)14.4 mm ( ) (d) 14.4x10-3 mm( ) = 2 Page Student ID Name 5. A weight falls on a collar rigidly attached to the lower end of a vertical bar 5 m long and 800 mm in section. If the maximum instantaneous extension is 2 mm, then stress in the bar in MPa will be (E = 200 GPa) (2 pts) (a) 40 MPa () (b) 100 MPa) (c)160 MPaC). (d) 80 MPa ( )