Pressure is the force per unit perpendicular area over which the force is applied. In equation form, pressure is defined as F=PA. The SI unit of pressure is pascal and \(1 \space Pa = 1 \space N...Pressure is the force per unit perpendicular area over which the force is applied. In equation form, pressure is defined as F=PA. The SI unit of pressure is pascal and 1Pa=1N/m2.