Answer: D=8.27 g/cm³
Explanation:
Density is mass/volume. Mass is in grams and volume is in liters. In this case, the problem wants our volume to be in cm³. All we need to do is to make some conversions to convert kg/m³ to g/cm³.

With this equation, the m³ and kg cancel out, and we are left with g/cm³.
D=8.27 g/cm³
Use mv=mv, plug in the know 1x9.24=3m. Solve for m, which m is 3.08M
Answer:
100 J of energy are needed to heat the copper from 20∘C to 80∘C .