As a country advances from an undeveloped nation to a modern industrialized nation, it changes in many significant ways. how ever, some parallels will remain. for example was used as an energy source by ancient civilization, and is still being used to produce energy today. a.) wind b.) fusión c.) eléctricity d.) volcanic ash

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.