What does waining mean?

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

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.

By what primary heat transfer mechanism does the sun warm the earth?