1. Method 1: If it is solid, the density of the ball is iron, otherwise it is hollow.

P ball =14000g/2.1*10 cubic meter < p Iron is hollow.

2. Compare the volume. If it is solid, the volume calculated according to the mass and density of iron is consistent with the lifted volume, so it is solid, otherwise it is hollow.

V = 14000g /7。 103g/cm3 < 2. 1

So empty

3. Compare the mass, assuming that the volume of 2. 1 is all iron, calculate whether the mass is consistent with the lifting, and if not, it is hollow.

M = 7.103 * 2.1*10 > the cube of kilograms.

Kong Xin

Volume: Vqiu-V iron =2. 1* 10 cubic meter-14000/7. 103