A mechanical interlock can prevent which of the following?

A mechanical interlock serves as a safety device designed to ensure that certain conditions are met before a machine can operate. Specifically, it is often employed to prevent machinery from functioning when safety guards are not properly positioned. This is crucial in maintaining a safe working environment, as the presence of protective guards is essential for preventing accidental injuries to operators or bystanders.

When the guard is not in place, the interlock disables the operation of the machine, ensuring that workers cannot inadvertently expose themselves to dangerous moving parts or other hazards associated with the machine's operation. This design helps enforce safety protocols by requiring that safeguards are in place, emphasizing the machine's dependency on these physical barriers for safe operation.

The other choices, while relevant to safety procedures, do not accurately describe the specific function of a mechanical interlock: it does not prevent operation when a guard is in position (which is safe) but rather prevents operation when the guard is absent.