75) The force acting along the circumference will cause stress in the walls in a direction normal to the longitudinal axis of cylinder; this stress is called

76) A boiler shell 200 cm diameter and plate thickness 1.5 cm is subjected to internal pressure of 1.5 MN/m , then the hoop stress will be

77) A cylindrical section having no joint is known as

78) Longitudinal stress in a thin cylinder is

79) The safe twisting moment for a compound shaft is equal to the