When the temperature of a metal cylinder is raised from 0.0°c to 110°c, its length increases by 0.22%. find the percent change in density.

Could someone me find the answer to this problem.

The air that we breath is made mostly of which gaseous molecule

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?