How is density of an object …

When an object is put in a liquid, then two forces act on it:

1. Weight of the object acting downwards.
2. Buoyant force acting upwards

Whether an object will float or sink in a liquid will depend on the relative magnitudes of these two forces acting on the object in opposite directions. Three cases arise:

1. If the buoyant force exerted by the liquid is less than the weight of the object, the object will sink in the liquid.
2. If the buoyant force exerted by the liquid is equal to the weight of the object, the object will float in the liquid.
3. If the buoyant force exerted by the liquid is more than the weight of the object, the object will rise in the liquid and then float.

So, we can conclude that an object will float in a liquid if the upward buoyant force it receives from the liquid is great enough to overcome the downward force of its weight.