What happens to a crane's rated capacity when it operates with an extended boom?

When a crane operates with an extended boom, its rated capacity decreases. This is primarily due to the mechanics of leverage and the distribution of weight. As the boom extends, it creates a longer moment arm, meaning that lifting loads at the end of this extended reach places greater stress on the crane's structure and stability.

The crane is engineered to handle specific loads within a certain range, and the further you extend the boom, the more the center of gravity shifts and the less load the crane can safely lift without risking tipping or structural failure. This principle is reflected in the manufacturer's load charts, which clearly outline how the capacity decreases as the boom length increases. Safety is a critical aspect here, as exceeding the rated capacity with an extended boom could lead to accidents or damage to the equipment and surrounding area.

The other options do not accurately reflect the engineering principles behind crane operation; for instance, the capacity does not increase when the boom is extended, nor does it remain unchanged. Similarly, load type does not generally affect the decrease in capacity when boom length is a factor.