Question

The shaft is supported at its ends by two bearings, A and B, and they are subjected to the forces applied to the pulleys fixed to the shaft. What is the purpose of the bearings?

1) To reduce friction between the shaft and the pulleys
2) To support the weight of the shaft and the pulleys
3) To transmit the forces from the pulleys to the shaft
4) To prevent the shaft from bending or breaking

Answer 1

Bearings primarily support the weight of the shaft and pulleys in a shaft and pulley system, while also reducing friction and preventing the shaft from bending or breaking under load.

Step-by-step explanation:

The primary purpose of the bearings in a shaft and pulley system is to support the weight of the shaft and the pulleys attached to it. They are designed to ensure that the shaft can rotate freely and efficiently by reducing the mechanical friction between the moving parts. When the pulleys exert forces, these forces translate into physical loads and torques on the shaft. Bearings allow the system to handle these forces without excessive wear and tear on the materials. This includes radial loads, which push down on the shaft, and axial loads, which run parallel to the shaft's rotation axis.

Additionally, well-designed bearings can help prevent the shaft from bending or breaking under the weight of the pulleys and the forces they transmit. However, reducing friction between the shaft and the pulleys isn't the main purpose of the bearings, as the pulleys typically do not make direct contact with the shaft; instead, they are fixed to it and rotate with it. Similarly, transmitting forces from the pulleys to the shaft isn't the role of the bearings since these forces are inherently transmitted through the physical connection of the pulleys to the shaft.