Being sold at an army surplus store is a pen gun. The pen gun fires a .22 caliber cartridge with a short barrel that has no rifling, so it must be shot at very close range such as 2ft or 3ft to do damage. What is the pen gun’s diameter in inches?

Asolid round steel rod 6.25 mm in diameter and 375 mm long is rigidly bonded to the end of solid square brass rod 25 mm on a side and 300 mm long. the geometric axes of the bare are along the same line. an axial tensile force of 5.4 kn is applied at the extreme ends of the assembly. for steel e = 200 gpa and for brass e = 90 gpa. determine the total elongation for the assembly.