What is the function of universal joints in tool use?

The function of universal joints in tool use primarily revolves around their ability to transmit rotational motion while allowing for a certain degree of angling between the connected components. This flexibility makes them particularly useful in situations where a straight line of action is not feasible.

In the context of turning nuts or bolts, the universal joint allows the handle of the tool to be held at various angles, making it easier to access fasteners in confined spaces or awkward positions. This capability is essential in mechanical applications, where a direct approach to a fastener may be obstructed by surrounding components or lack of space.

While the other options may reference aspects of tools, they do not accurately capture the unique functionality provided by universal joints:

• The movement of the handle mentioned in the first choice is not specific to the tasks that universal joints are designed to assist with.

• Connecting rods at a 90-degree angle is a function more suited to specific mechanical linkages rather than the universal joint's flexibility.

• Holding fasteners securely pertains to the clamping or fastening mechanisms rather than the motion flexibility that universal joints provide.

Thus, the ability to operate under angled conditions while effectively transferring torque to turn fasteners distinguishes the application of universal joints in tools.