Which of the following actions can mechanical power transmission systems perform?

Mechanical power transmission systems are designed to effectively transmit power and motion in various forms. One of the key capabilities of these systems is their versatility in performing multiple actions.

Firstly, they can reverse the direction of rotation, allowing a machine to operate in both clockwise and counterclockwise directions. This feature is essential in many applications, for instance, in applications like conveyor belts that need to move in either direction.

Secondly, these systems can change the axis of rotation angle. This is particularly useful in configurations where the orientation of the output shaft or movement needs to be adjusted, such as in certain types of gear systems and universal joints.

Additionally, mechanical power transmission can convert between rotary and linear motion. For example, a rotary motion from a motor can be converted into linear motion through mechanical linkages, such as in screw jacks or belt-driven systems.

By encompassing the ability to reverse rotation, adjust the angle of rotation, and convert motion types, these systems demonstrate their comprehensive role in mechanical engineering. Therefore, the conclusion that they can perform all of the mentioned actions is accurate and reflects their broad functionality in various mechanical applications.