The ergonomic principle that best aligns with positioning a display screen for optimal view is Neutral Posture. This principle minimizes muscle strain by keeping the body's center of gravity properly aligned, thereby preventing back strain and muscular fatigue associated with prolonged sitting and looking at a screen.
The ergonomic principle that aligns best with the statement "A display screen should be positioned so it is viewable by looking straight ahead or slightly down" is Neutral Posture. When setting up an ergonomic workspace, maintaining a neutral posture is vital to prevent strain and ensure comfort. This means sitting or standing in a way where the body's center of gravity is above the pivot point in the hips, avoiding torque around the hips that can cause back strain and necessitate forceful muscle actions. Ergonomically designed chairs and desk setups help support this position, creating an environment that reduces the risk of repetitive strain injuries.
Moreover, when the display screen is set at a proper height where one can look straight ahead or slightly downwards, it enforces good posture and reduces the risk of ergonomic seating-related issues. The main answer to why the body's center of gravity should be situated in such a manner is because it will be directly above the base of support, minimizing the need for muscle exertion and thus reducing the likelihood of repetitive strain. Proper ergonomic seating supports this neutral position and aims to minimize wrist extension and other forms of strain.