When an object is at rest ,we say forces are?

If an object is at rest, then there are no forces acting on the object. It would take an unbalanced force to keep an object in motion at a constant velocity. It is the natural tendency of all objects to eventually come to a rest position.

Explanation:

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3