Q. Which of the following is/are correct for thrust and pressure?
- The force acting on an object perpendicular to the surface is called thrust.
- The thrust on unit area is called pressure.
- SI unit of pressure is called pascal.
Select the correct answer from the codes given below:
Answer:
All of the above
Notes: The force acting on an object perpendicular to the surface is called thrust. When you stand on loose sand, the force, that is, the weight of your body is acting on an area equal to area of your feet. When you lie down, the same force acts on an area equal to the contact area of your whole body, which is larger than the area of your feet. Thus, the effects of forces of the same magnitude on different areas are different. In the above cases, thrust is the same. But effects are different. Therefore the effect of thrust depends on the area on which it acts. The effect of thrust on sand is larger while standing than while lying. The thrust on unit area is called pressure. Thus,
- thrust= Pressure/area. The SI unit of pressure is N/m2 or Nm-2 .
In honour of scientist Blaise Pascal, the SI unit of pressure is called pascal, denoted as Pa.