Which of the following forces does NOT have a zero work done on the object.

Choices
The normal force on a box that slides across a horizontal level floor.
The weight on a box that slides across a horizontal level floor.
The normal force on a box that slides down an inclined plane.
The weight on a box that slides down an inclined plane.
Actually all of the above describe forces that do zero work

To determine which force does NOT have a zero work done on the object, we need to understand the concept of work done by a force.

The work done by a force on an object is equal to the product of the force applied on the object and the displacement of the object in the direction of the force.

Now let's analyze each choice to determine the work done by the forces mentioned:

1. The normal force on a box that slides across a horizontal level floor:

The normal force acts perpendicular to the surface and does not cause any displacement in the direction of the force. Therefore, the work done by the normal force is zero.

2. The weight on a box that slides across a horizontal level floor:

The weight of an object acts vertically downward, while the displacement of the object while sliding horizontally is perpendicular to the weight. As the displacement is perpendicular to the direction of the weight, the work done by the weight is zero.

3. The normal force on a box that slides down an inclined plane:

In this case, the normal force still acts perpendicular to the surface, but now there is a component of the displacement in the direction of the normal force. The normal force does not cause any net displacement in the direction of its own force, so the work done by the normal force is still zero.

4. The weight on a box that slides down an inclined plane:

The weight of the object acts vertically downward, but now there is a component of the displacement in the direction of the weight. As the weight causes a net displacement in the direction of its own force, the work done by the weight is not zero.

Therefore, the force that does NOT have zero work done on the object is the weight on a box that slides down an inclined plane.