how if the weight of the object increase , the buoyant force increase????

Dear student,
Weight is a measure of the force of gravity pulling down on an object, whereas buoyant force pushes up on an object. Which force is greater determines whether an object sinks or floats.
Buoyant force occurs because the fluid below an object exerts greater pressure on the object than the fluid above it. If an object's weight is less than the buoyant force acting on it, then the object floats. Therefore, density of an object also affects whether it sinks or floats.
The factors that affect buoyancy are

• the density of the fluid, the volume of the fluid displaced, and. the local acceleration due to gravity.

• The buoyant force is not affected by… the mass of the immersed object or. the density of the immersed object.

Regards