The heaviest weight that can be picked by a digger derrick is achieved when the boom is what?

The heaviest weight that can be lifted by a digger derrick is achieved when the boom is fully retracted. When the boom is in this position, it is closer to the machine's center of gravity, which allows for greater stability and support when lifting heavy loads. A fully retracted boom minimizes the leverage exerted on the machine, which is crucial for safely lifting heavier items.

In contrast, when the boom is fully extended or at a shallow angle, the center of gravity shifts, increasing the risk of tipping and reducing the overall capacity for lifting heavy objects. This is because extending the boom uses leverage that can compromise stability, making it less capable of handling maximum weights safely. Therefore, positioning the boom fully retracted optimizes the machine's lifting capacity and overall stability, enabling it to pick the heaviest loads effectively and safely.