If the buoyant force is less than the weight of an object put in a fluid, the object will sink.

Here's why:

* Buoyant force is the upward force exerted by a fluid on an object submerged in it.

* Weight is the force of gravity acting on the object's mass.

When the buoyant force is less than the weight, the downward force of gravity is stronger. This means the object will be pulled downwards by gravity, causing it to sink.