The correct answer is option 3, which states that the weight of an object is due to the force that it exerts on the ground.
Let`s dissect the other options to get a better understanding:
Option 1 suggests that the weight of an object is due to the net force acting on it. While net force does play a role in the motion of an object, it is not directly responsible for its weight. Weight is specifically the gravitational force exerted on an object, not the net force.
Option 2 suggests that the weight of an object is the total of all forces acting on it, irrespective of their directions. This statement is incorrect because weight is a specific force due to gravity, and is not influenced by other forces acting on the object, such as friction or air resistance.
Option 4 suggests that weight is due to an object`s inert property. Inertia is the tendency of an object to resist changes in its motion, but it is not directly related to an object`s weight. Weight is specifically the force experienced by an object due to gravity.
In conclusion, option 3 correctly states that the weight of an object is due to the force that it exerts on the ground. This force is specifically the gravitational force acting on the object.