Final answer:
The support bearings at points A and B allow free turning of the shaft.
Step-by-step explanation:
The subject of this question is Physics. The question is asking about the support bearings at points A and B that allow free turning of the shaft. When we have support bearings at points A and B, it means that the shaft is able to rotate freely without any resistance or restrictions from the bearings. This allows the shaft to rotate smoothly and perform its intended function.