the strength of the shaft

the rigidity of the shaft

both the strength and rigidity of the shaft

the ductility of the shaft

Correct

Incorrect

Torque in each shaft is the same

Shear stress in each shaft is the same

Angle of twist of each shaft is the same

Torsional stiffness of each shaft is the same

Correct

Incorrect

square threads

acme threads

knuckle threads

buttress threads