Massa pelat aluminium 135 gram . jika volumenya 50 cm barapa massa jenisnya dalam kg/m

M (massa) = 135 gr = 135.10^-3 kg
V (volume) = 50cm³ = 5.10^-5 m³
massa jenis = m/V = 135.10^-3 / 5.10^-5 = 27.10² = 2700 kg/m³