What is the primary reason a sharp needle pierces the skin more easily than a blunt object with the same force?
Pressure is defined as force per unit area (P = F/A). A sharp needle has a smaller contact area, resulting in higher pressure for the same force, making it easier to penetrate the skin compared to a blunt object with a larger area.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.