Is the primary purpose of a key to transmit momentum?

The primary purpose of a key is not to transmit momentum but rather to prevent relative movement between two parts, often a shaft and a hub in machinery. Keys serve as mechanical devices that fit into the keyways of the shaft and hub, providing a secure connection that allows torque to be transmitted while aligning the components. This means that their main function revolves around ensuring that rotational force is effectively transferred to drive a connected component, rather than transmitting momentum, which refers to the motion of a body and is dependent on mass and velocity.

Momentum is a physical quantity related to the motion of objects, while keys are specifically designed for mechanical fastening and alignment. Therefore, the statement regarding the primary purpose of a key is false, as it focuses on the transmission of momentum rather than on the key’s function in maintaining fixed relationships between components.