Answer
A sharper tool has a smaller area and exerts a greater pressure with the same amount of force than a blunt tool with a greater surface area on the point.
Work Step by Step
A sharp pin can pierce your skin when pushed with a certain force, though the same force does not cause the blunt end of a pen to pierce your skin. The pressure (force per unit area) applied by a tool determines whether your skin is pierced, not the net force applied.