In a Flexible manufacturing system, the Automated Guided Vehicles $$(AGV)$$ move at a speed of $$50$$ $$m/min,$$ cover an average distance of $$150$$ $$m$$ to deliver and $$100$$ $$m$$ for return. If the time required for pick-up and drop is $$30$$ $$s$$ each, neglecting idle times, then the number of $$AGV$$$$s$$ required to meet the demand of $$50$$ delivers per hour is ____________.

The true stress at fracture of a tensile tested specimen, having an initial diameter of specimen at fracture is $$10$$ $$mm,$$ then the engineering stress, in $$MPa,$$ at fracture is ____________

In rolling of a flat strip, the relative velocity of strip with respect to the roller is

The maximum reduction per pass during wire drawing of an aluminium alloy ignoring friction and redundant work is $$77\% $$. The strain hardening exponent of the material is ______________.