IM DOING ONE MORE GIVE AWAY AFTER THIS ONE SO BE READY!!!

In science and physics what is the standard unit of measure for speed?

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.

The energy produced as a result of this flow of electrons from atom to atom is called