You press a knife with 40 N. Its edge is 8 cm long…

Step 1. Sharp. Area $0.08\ \text{m} \times 0.0005\ \text{m} = 4 \times 10^{-5}\ \text{m}^2$: $\dfrac{40\ \text{N}}{4 \times 10^{-5}\ \text{m}^2} = 1.0 \times 10^{6}\ \text{Pa}$.

Step 2. Blunt. Area $1.6 \times 10^{-4}\ \text{m}^2$: $2.5 \times 10^{5}\ \text{Pa}$.