Question

A piece of alloy weights 0.86N in air and 0.73N When Immersed in water. Find volume and the density of the alloy

Answer 1

The weight of alloy in water

$$W=mg-g\rho V$$

The volume of alloy

$$V=\frac{mg-W}{g\rho}\\ =\frac{0.86-0.73}{9.8*1000}=1.33*10^{-5}\:\rm m^3$$

The density of alloy

$$\rho_a=\frac{m}{V}\\ =\frac{0.86}{9.8*1.33*10^{-5}}=6615\:\rm kg/m^3$$