When drilling a hole in a table leg, a furniture maker uses a hand-operated drill with a bit of diameter d=4.0mm.
(A). If the resisting torque supplied by the table leg is equal to 0.3 Nm, what is the maximum shear stress in the drill bit?
(B). If the allowable shear stress in the drill bit is 32 MPa, what is the maximum resisting torque before the drill binds up?
(C). If the shear modulus of elasticity of the steel is G=75 GPa, what is the rate of twist of the drill bit (degrees per meter)?