# Rods, Springs, and Strings

You can set up pendulums, vertical springs and other systems by linking balls and blocks to rods, springs, or strings. Drag the rod, spring, or string to reveal connection pads in the centres of any balls or blocks in the scene. You can then link the part by dragging the end of the rod, spring, or string on to a connection pad.

Tips for use:

- Rods, springs and strings have no mass.
- Free ends are automatically fixed in position during simulation.
- Drag on the free end of the rod, spring, or string to increase its length.

## See also:

- Balls and Blocks
- Using motion parts