There isn't a force that makes objects fall at different speeds. All objects fall at the same rate in a vacuum, regardless of their mass or composition. This is due to the force of gravity.

Here's why different objects might appear to fall at different speeds in the real world:

* Air resistance: Air resistance is a force that opposes the motion of objects through the air. It depends on factors like the object's shape, size, and speed. Objects with larger surface areas or less streamlined shapes experience more air resistance, causing them to fall slower. This is why a feather falls much slower than a rock.

* Mass and density: While gravity pulls on all objects equally, heavier objects have more inertia (resistance to change in motion). This means they need more force to accelerate, so heavier objects might appear to fall slower if air resistance is significant.

The key takeaway is that the force of gravity pulls on all objects equally, and in a vacuum, they would fall at the same rate. Air resistance is the primary reason why objects fall at different speeds in our atmosphere.