What must you obtain before leaving the mechanics laboratory?

Obtaining permission from the instructor before leaving the mechanics laboratory is essential for several reasons. This requirement ensures that safety protocols are followed, as instructors are responsible for maintaining a safe learning environment. They need to be aware of who is present in the lab, especially when students are using tools and equipment that can pose risks if not handled properly. Furthermore, instructors can verify that all tasks are completed and all equipment is secured before students exit, which is crucial for the safety of everyone in the lab.

In contrast, seeking permission from a fellow student, as mentioned in another option, does not address safety or accountability. Fellow students may not have the authority to ensure a safe environment or to know if all procedures have been followed. Additionally, leaving without any permission can lead to misunderstandings or safety hazards, as instructors may need to know where students are at all times for their safety. Furthermore, permission from a parent is typically not appropriate in a school laboratory context, as parents are not present and do not have a direct role in the supervision of the lab activities.