China Naming Network - Almanac query - How to judge whether a copper ball is solid or hollow?
How to judge whether a copper ball is solid or hollow?
By calculation!
Example: The mass of the copper ball is 178g and the volume is 40 cubic centimeters. Is it hollow or solid? (Explain in three ways)
1) quality method:
If the copper ball is solid, its mass m should be:
M = v * ρ = 40 * 8.9g = 356g。
But in fact, the mass is only 178g, so it is hollow.
2) Volume method
If the copper ball is solid, its volume v is:
V=m/ρ= 178/8.9=20 cubic centimeters.
But the actual volume is 40 cubic centimeters, so it is hollow.
3) Density method
If a copper ball is solid, its density is:
ρ = m/v = 178/40 = 4.45g/cm3。
Obviously, the density less than copper is 8.9 g/cm3.
Therefore, it can only be hollow
Hope to adopt!