The force being tested when an object is forced downward toward the center of the Earth is gravity.

Here's why:

* Gravity is the force of attraction between any two objects with mass. The Earth has a large mass, so it exerts a strong gravitational pull on objects near its surface.

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

* When you force an object downward, you are essentially overcoming its inertia and accelerating it in the direction of the Earth's center of mass.

While other forces might play a role depending on the specifics of the scenario (like air resistance), the fundamental force being tested in this situation is gravity.