1. Left drag the objects circled in red in the following diagram to alter their positions.
2. Left click anywhere outside the circled regions to display the forces and the moment arms.
3. Right click (or control-click) anywhere and then drag the whole system to move.
4. The beam is capable to be turned to any position, but not vertically.
5. The masses of the beam and the spring balance are neglected.
6. If the beam "collapses" unfortunately, reset the page and start again