Grommet be used purely decoratively for crafting. When used in sailing and various other applications, they are called cringles. Sometimes field workers refer to them as grunyons. If metal or another hard material has a hole made in it, the hole will probably have sharp edges. Electrical wires, cord, rope, lacings, or other soft vulnerable material passing through the hole can become abraded or cut, or electrical insulation may break due to repeated flexing at the exit point. Rubber, plastic or plastic coated metal grommets are used to avoid this. The grommet could also protect the wiring/cabling from contamination from dirt,
Ant on a rubber rope a given time formula_36 is its speed relative to the rope, i.e. formula_18, plus the speed of the rope at the point where the ant is. The target-point moves with speed formula_38, so at time formula_39 it is at formula_40. Other points along the rope move with proportional speed, so at time formula_39 the point on the rope at formula_42 is moving with speed formula_43. So if we write the position of the ant at time formula_39 as formula_45, and the speed of the ant at time formula_39 as formula_47, we can write: This is a first order linear differential