Pressure
Pressure is the ratio of the force applied to a surface area. The unit of pressure is measured in pascals (Pa). The knives we use in our everyday life need to be sharp to be used optimally. A blunt knife is practically useless. The force that is applied perpendicular to the surface of a particular object, the force gets distributed over it. The lesser the surface area higher the pressure and the sharper the knife.
The formula of pressure is pressure = force/area. Pressure is measured in Pa. When a force of one newton gets applied over an area that is one meter squared, the pressure that is generated is equal to one pascal.
We can increase or decrease the pressure without changing the force by changing the area over which the force is acting. The lesser the surface area, the higher the pressure. The pressure becomes higher when the area gets smaller. In a sharp knife, the force is distributed over a small surface area which makes the knife very easy to use. In a blunt knife, the force is distributed over a large surface area; therefore, the pressure becomes less, and the knife gets harder to use.
Pressure in fluids
The particles which are present in a fluid can move in all directions; therefore, if an object gets immersed in water, pressure will act on it in all directions. There are continuous collisions between these molecules that cause the pressure.
Pressure in gases
The particles in gases have random motion; therefore, when they get heated, they become excited, and their kinetic energy increases. As kinetic energy increases, there will be more collisions, and the pressure exerted will increase.
Equations involving pressure
A brick exerts a force of 25 newtons on an area of 2 meters squared; what is the pressure of the brick on the ground?
- Putting it into the equation, pressure = 25/2 = 12.5 pascals.
A bowl exerts a force of 26 newtons on an area of 2 meters squared; what is the pressure of the bowl on the ground?
- Putting it into the equation, pressure = 26/2 = 13 pascals.
An oven exerts a force of 28 newtons on an area of 2 meters squared; what is the pressure of the oven on the table?
- Putting it into the equation, pressure = 28/2 = 14 pascals.