How many kilograms or more of material should machinery and tools be used instead of manpower as much as possible?

Using machinery and tools instead of relying on manpower when handling materials is crucial for safety and efficiency in the workplace. The correct answer is determined based on guidelines that suggest a specific weight threshold where mechanical assistance becomes advisable.

The threshold of 40 kilograms is grounded in safety regulations and ergonomic principles, indicating that lifting or moving items heavier than this amount can increase the risk of injury, particularly musculoskeletal disorders. This is particularly important in settings like warehouses and factories, where repetitive lifting and manual handling can lead to long-term health consequences for workers.

When items weigh 40 kilograms or more, the physical strain on the body increases significantly, making the task not only physically demanding but also potentially hazardous. Machinery or tools, such as forklifts, pallet jacks, or hoists, can mitigate these risks by allowing operators to move heavy loads without putting themselves at risk.

The other options, while they suggest lower weight limits, do not accurately reflect the recommended threshold for when it becomes crucial to transition from manual handling to the use of mechanical aids. Operating with a higher threshold helps ensure the safety and well-being of employees while maximizing productivity.