Have you ever given a thought – How a camel can run in a desert easily, or why a motor truck or a motor bus has much wider tyre, or why cutting tools have sharp edges? Here, In this lesson we will learn some new concepts in physics which answer all these questions. They are the net force acting in a particular direction called as the “Thrust”. And the force acting per unit area, which we are already aware about called as the “Pressure”. Let’s try to understand this in detail. I guess all of us like to do some or the other extracurricular activities. Just imagine that you want to fix some of your drawings, poems or stories on your school notice board. What will you do ? To do this task, you will be pressing the drawing pin with your thumb, right ? you apply a force on the head of the pin. The force is acting perpendicular on the board, this force which is acting on a particular direction is called as the “Thrust”. Or you stand on loose sand, you feel that your legs are going into the sand. Now lie on the sand, what do you feel? You feel that your body is not going that deep into the sand. In both the cases, the force exerted is the weight of your body. Now, when you stand the force that is the weight of your body is exerted on the area which is equal to the area of your feet. And when you lie down, the force that is the weight of your body is exerted on the whole contact area of your body. Thus, the forces of same magnitude are different for different areas. In both the cases the trust is the same. Though the trust is the same, the effect of trust depends on the area of contact. So the thrust acting on unit area is called “pressure”. Pressure is equal to thrust upon unit area. By substituting the values of or the S.I. unit of thrust and area, we get the S.I. unit of pressure as newton per meter square. But in the honour of the scientist Blaise Pascal, the S.I. unit of pressure is called as pascal, which is denoted as Pa. Here in this lesson we have learned about some interesting concepts in physics such as thrust which is force acting on a particular direction and pressure which is thrust acting on a unit area.