# Torque and angle of rotation in linked shafts

- Author:
- rwmoss

- Topic:
- Rotation

This applet should help you to understand how to:

- 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).

- 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.