Final answer:
The statement is false; the Y-balance test assesses injury risk. The book and weight will balance on Earth and the moon due to constant relative mass, but this is unrelated to the given test.
Step-by-step explanation:
The statement is False. The Y-balance test is indeed used to assess soccer players' risk of sustaining lower extremity injuries. However, the scenario involving a book and a 1-kg iron weight on a balance scale is related to the principles of physics, particularly relating to gravity. If the book and the iron weight balance each other on Earth, they will also balance on the moon because balance scales measure relative mass, which does not change regardless of location. While the force of gravity is less on the moon, the relative masses of the book and the 1-kg weight remain the same, ensuring the balance stays level. The concept of equilibrium in physics, such as the net external forces along the y-axis and x-axis being zero, further supports the understanding of why objects in balance remain in balance when taken to the moon.