Assembling a steel rod with a universal joint likely affects its natural frequency due to changes in stiffness. The discussion emphasizes the need for more detailed information to provide a definitive answer. The term "rigidly fixed" suggests minimal gross motion, yet the inclusion of a universal joint implies potential for significant rotational movement. This contradiction creates confusion, highlighting the importance of visual aids, such as diagrams or pictures, to clarify the setup. Overall, understanding the interaction between the components is crucial for assessing the impact on natural frequency.