Răspuns:
d(al) = m(al)/V(al) => V(al) = mal/dal = 32.4g/2.7g/cm³ = 12 cm³
Vcub = l³ = (8cm)³ = 512 cm³
Vlemn = 512cm³ - 12cm³ = 500cm³
m(lemn) = d(lemn)×V(lemn) = 0.55g/cm³×500cm³ = 275 g
m(cub) = 275g + 32.4g = 307.4g = 0.307kg
Fe = Δl×k
Fe = G } => G = Δl×k => Δl = G/k
Δl = 0.3074kg×9.8N/kg/50N/m
= 3.01252N/50N/m
= 0.0602504m
= 6.02504 cm