Data: V – the volume of the cast iron weight taken (V = 80 cm3; in the SI system V = 8 * 10 ^ -5 m3); mchg is the mass of the cast iron weight (mchg = 500 g; in the SI system mchg = 0.5 kg).
Const: ρh – density of cast iron (ρh = 7000 kg / m3).
If there is no cavity inside the cast iron weight taken, then the equality will be fulfilled: ρch = ρg.
ρh = mchg / V.
7000 = 0.5 / (8 * 10 ^ -5).
7000 kg / m3 ≠ 6250 kg / m3 (wrong).
Answer: There is a cavity inside the cast iron weight taken.
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