question_answer

The frictional torque for square thread at mean radius while raising load is given by \[(W=load,\,{{R}_{0}}\,=\,\]Mean Radius,\[\phi =\]Angle of friction, \[\alpha \,=\,\]Helix angle):

A) \[W{{R}_{0}}\tan (\phi -\alpha )\]           

B) \[W{{R}_{0}}\tan (\phi +\alpha )\]

C) \[W{{R}_{0}}\tan \alpha \]                    

D) \[W{{R}_{0}}\tan \phi \]