This challenge is about elastics.
We begin with 2 elastics. Elastic A has nominal length 3 centimetres and spring constant 2 kilograms per square second. This notation seems unfamiliar but remember that we multiply by the displacement, in metres, and get a force, in mkg/s2. Elastic B has nominal length 5 centimetres and spring constant 3 kg/s2. The long elastic it threaded through the small one. The 2 ends of the long elastic are folded together. 2 identical rods are threaded through them. They are then pulled apart. The elastics are held in place at equal heights on the rods so they cannot move up or down. They are at equal heights and can rotate frictionlessly. The rods are then fastened to the surface of the earth some distance apart. The rods do not sway, bend, or in any way stop being vertical. A weight is placed halfway between the 2 rods, resting on the elastics. It weighs 1 gram. The weight does not cause any friction on the elastics. Elastics A and B are stretched to equal lengths. How far apart are the rods?