Upthrust = change in weight density = \(\frac{\text{mass}}{\text{volume}}\) Mass of liquid displaced = Density of Liquid \times Volume; = \(10^{3} \times 50 \times 10^{−6}m^{3}\) = 0.05kg (Note that the volume of \(50cm^{3}\) was converted to \(m^{3}\) by multiplying by \(10^{6}\)) i.e \(50cm^{3} = 50 \times 10^{−6}m^{3}\) Since mass displaced = 0.05kg Upthrust = mg = 0.05 \times 10 = 0.5N