Final answer:
Manually adjusting the struts of a screw jack system is hazardous due to the need to exert physical force, which can lead to strain or injury without the mechanical advantage systems like hydraulic jacks provide. Specialized abilities and training are crucial for safely operating heavy machinery that uses such systems.
Step-by-step explanation:
The student's question pertains to the hazards associated with manually adjusting the struts of a screw jack system, used in applications such as lifting heavy loads like vehicles. The hazard in this context arises because the worker is required to exert physical force. This is similar to the application of force described in hydraulic systems like jacks, where a small force applied to one side can lift heavy loads due to the mechanical advantage provided by the system. However, manual screw jack systems do not use hydraulics and require significant manual effort, which poses a risk of physical strain or injury to the worker. Moreover, tasks such as operating heavy machinery require specialized abilities and training to ensure safe and effective operation.
An example related to hydraulics that illustrates the use of force multiplication is when mechanics put a length of pipe over the handle of a wrench to remove a tight bolt. This increases leverage and allows for greater torque to be applied with less physical strength, but also brings the risk of overexerting force and breaking the bolt. In mechanical systems like screw jacks, the user similarly must apply effort, but without the mechanical assistance that systems like hydraulic jacks or extended levers provide, hence increasing the potential for hazard.