Question

A piece of gold-alminium alloy weighs 49N. When suspended from a spring balance and submerged in water it weighs 39.2N. What is the weight of Gold in the alloy the specific gravity of gold is 19.3 and that if aluminium is 2.5? ​

Answer 1

The mass of the water in 1 kg (9.8 N = m (9.8 m/s/s)),

Thus the volume of the water is 1000 ml.

5 = (Mau + Mal)/(Vau + Aal)

(Density = total mass to the total volume)

We know that:

19.2 = Mau/Vau and 2.5 = Mal/Val.

We have to find the volume. Therefore,

5Val + 5Vau = Mau + Mal

5(Mal/2.5) + 5(Mau/19.2) = Mau + Mal

Mal = 0.74 Mau

5 kg = M(au) + (1/.74)M(au)

=> M(au) = 2.13 kg

Weight of gold = 20.8 N

hence the weight of the gold is 20.8 N