Distinguish between thrust and pressure. Write their units. What is the relation between them? Explain an application where we reduce pressure acting on a body.

Thrust and pressure are two different physical quantities related to the behavior of fluids or gases. Let's distinguish between them and explain their units:

Thrust:
Thrust is the force that propels an object in a particular direction. It is typically associated with the motion of fluids or gases. Thrust occurs due to the reaction force generated by accelerating or expelling a mass of fluid or gas in the opposite direction. In other words, thrust is the force exerted on an object perpendicular to its surface due to the movement or ejection of a fluid or gas.
Unit of thrust: The unit of thrust is Newton (N) in the International System of Units (SI).

Pressure:
Pressure is the force exerted per unit area on the surface of an object. It is the measure of how much force is distributed over a certain area. Pressure can be exerted by fluids or gases in all directions and is defined as the ratio of force to the area over which the force is distributed.
Unit of pressure: The unit of pressure is Pascal (Pa) in the SI system. Another commonly used unit of pressure is pounds per square inch (psi).

Relation between thrust and pressure:
Thrust and pressure are related to each other through the area over which the force is distributed. Mathematically, pressure (P) is defined as force (F) divided by the area (A) over which the force is applied:
P = F / A

Hence, pressure is directly proportional to the force applied and inversely proportional to the area over which the force is distributed.

Application of reducing pressure acting on a body:
One application where we reduce pressure acting on a body is in aerodynamics and fluid dynamics, specifically in the design of streamlined shapes. By reducing the pressure acting on a body, we can minimize drag forces and increase efficiency.

For example, consider an airplane wing. Air flows over and under the wing as the plane moves forward. According to Bernoulli's principle, as the air flows faster over the curved upper surface of the wing, the pressure decreases. To reduce the pressure acting on the wing, the shape of the wing is designed to create a longer path for the air over the top surface, causing it to move faster and thus reducing the pressure. This pressure difference between the upper and lower surfaces of the wing generates lift, allowing the airplane to fly.

In summary, by reducing the pressure acting on a body, we can manipulate the forces exerted by fluids or gases, leading to applications such as aerodynamic lift, reducing drag, and increasing the efficiency of various fluid-based systems.