Define the pascal (Pa), the S.I unit of pressure.

The pascal (symbol: Pa) is the SI (International System of Units) unit of pressure. It is named after the French mathematician, physicist, and philosopher Blaise Pascal. One pascal is defined as one newton per square meter (N/m²).

To understand this definition, let's break it down:

Newton (symbol: N) is the SI unit of force. It is a measure of the amount of force required to accelerate a mass of one kilogram by one meter per second squared (N = kg · m/s²).

A square meter (symbol: m²) is a unit of area, which represents the area of a square with sides of one meter in length.

Therefore, one pascal is equal to one newton of force applied uniformly over an area of one square meter. This means that a pressure of 1 pascal is a very small amount of force spread out over a large area.

In practical terms, the pascal is often used for measuring small pressures. However, for larger pressures, kilopascals (kPa) or megapascals (MPa) are commonly used. For example, atmospheric pressure at sea level is approximately 101.3 kilopascals (101.3 kPa) or 101,300 pascals (101,300 Pa).