The shear force is a force that acts parallel to the surface of an object, causing it to deform or slide. When the shear force creates a clockwise rotation, it means that the force is causing the object to rotate in the clockwise direction. In this case, the correct answer is option 'A', which states that the force is said to be positive.

Here is a detailed explanation of why the force is considered positive in this scenario:

Definition of shear force:
- Shear force is a force that acts parallel to the surface of an object, causing it to slide or deform. It is typically represented by the symbol 'V' and is measured in units of force (such as Newtons or pounds).

Clockwise rotation:
- Clockwise rotation refers to the rotation of an object in the direction of a clock's hands. It is a rotational motion that occurs when a force causes an object to rotate in the clockwise direction.

Positive shear force:
- In engineering and mechanics, positive shear force is often defined as a force that causes a clockwise rotation. This convention is used to simplify calculations and analysis of structures and systems.

Explanation:
- When a shear force acts on an object and creates a clockwise rotation, it means that the force is causing the object to rotate in the same direction as the hands of a clock. This is considered a positive shear force.
- By convention, positive shear force is often represented by an arrow pointing in the direction of the shear force and labeled with a positive sign (+).
- This convention allows engineers and analysts to determine the effects of shear forces on structures and systems without having to consider the specific direction of rotation.

In conclusion, when the shear force creates a clockwise rotation, the force is considered positive. This convention simplifies calculations and analysis in engineering and mechanics.