Suppose a bar 1 m long expands .5 cm when heated. By how much will a bar 100 m long of the same material expand when similarly heated?

If each one meter expands a half centimeter, then one hundred meters will expand 100*.5cm. Think on that.

NO I DON'T UNDRERSTAND WHAT THAT MENS
THERMAL ENERGY MEANS

If there is a positive change in Thermal Energy is there a gain or loss in energy?

fmdmid?