# Torque and angle of rotation in linked shafts

Author:
rwmoss
Topic:
Rotation
• use either outward or inward arrows to define a "positive torque" in accordance with the right-handed rule,
• draw graphs showing the variation of torque and twist along a shaft
• use superposition to combine the torques and twists due to external torques applied at two different locations (B, C).
Remember
• the RH rule only defines what a torque vector (arrow) means; as with any mechanics problem, it is up to you to draw a diagram with arrows showing what you have chosen as the positive direction for each force or torque vector.
• "arrows outward": positive torque makes the shaft twist such that, looking along it, the angle of twist is increasingly clockwise as one looks further away. This torque would unscrew a conventional nut and bolt.
• "arrows inwards": positive torque makes the shaft twist such that, looking along it, the angle of twist is increasingly anti-clockwise as one looks further away. This torque would tighten up a nut and bolt.