Question

A steel plate measures 500mm×200mm×10mm. If the relative density of the steel is 7.8 ,calculate the mass of the plate

Answer 1

1 cm = 10 mm.

Therefore, the volume of the plate in cm³ equals:

$V=50\ cm\times20\ cm\times1\ cm=1000\ cm^3$

Since the relative density of 7.8 refers to 7.8 g/cm³,

$mass=density\times{volume}=7.8\ g/cm^3\times1000\ cm^3=7800\ g=7.8\ kg$

Answer: 7.8 kg