Explain briefly why a kitchen knife is sharp in order to cut a piece of yam easily. A force of 10 Newton is exerted on a piece of yam using a knife of cross-sectional area 1x10⁻⁵ m2. Determine the pressure exerted. State 3 applications of pressure.

Given:  
Force ($F$) = $10 \text{ N}$  
Cross-sectional area ($A$) = $1 \times 10^{-5} \text{ m}^2$  
The formula for pressure is:
$$
P = \frac{F}{A}
$$

$$
P = \frac{10 \text{ N}}{1 \times 10^{-5} \text{ m}^2}
$$

$$
P = 10 \times 10^{5} \text{ Pa}
$$
$$
P = 1,000,000 \text{ Pa}
$$
$$
P = 1 \times 10^{6} \text{ Pa}
$$
The pressure exerted is $\boxed{\text{}1 \times 10^{6} \text{ Pa}}$.