Air resistance The weight of the box The frictional force exerted by the floor on the box The gravitational force exerted by the Earth on the box
To keep a heavy box sliding across a carpeted floor at constant speed, a person must continually exert a force on the box. This force is used primarily to overcome which of the following forces?

Options:
- Air resistance
- The weight of the box
- The frictional force exerted by the floor on the box
- The gravitational force exerted by the Earth on the box

The frictional force exerted by the floor on the box