The state of stress at a point is given by $$\,\,{\sigma _x} = - 6\,MPa,\,\,{\sigma _y} = 4\,\,MPa,$$ and $${\tau _{xy}} = - 8\,\,MPa.$$ The maximum tensile stress (in MPa) at the point is ____________.

A pair of spur gears with module $$5$$ $$mm$$ and a center distance of $$450mm$$ is used for a speed reduction of $$5:1$$. The number of teeth on pinion is _________

A hydrodynamic journal bearing is subject to $$2000$$ $$N$$ load at a rotational speed of $$2000$$ $$rpm.$$ Both bearing bore diameter and length are $$40mm.$$ If radial clearance is $$20\mu m$$ and bearing is lubricated with an oil having viscosity $$0.03$$ $$Pa.s,$$ the Sommerfeld number of the bearing is _______

The major difficulty during welding of aluminium is due to its