Final answer:
The word 'needle' in associative meaning can be described as a sharp instrument made of steel. The sharpness of a knife or a hypodermic needle is related to pressure. A dull hypodermic needle hurts more than a sharp one because it requires more pressure to penetrate the skin.
Step-by-step explanation:
The word 'needle' in associative meaning can be described as a sharp instrument made of steel. In the context of the question, the word 'needle' refers to a sharp object commonly used in medical procedures, like injections. The sharpness of a knife or a hypodermic needle is related to pressure because pressure is directly proportional to the force applied over an area. Applying a smaller force over a smaller area creates a higher pressure, which results in a sharper edge. A dull hypodermic needle hurts more than a sharp one because it requires more pressure to penetrate the skin. The increased pressure can cause damage to the surrounding tissues, resulting in more pain.