Pressure
Pressure is a fundamental concept in physics and engineering that quantifies the force exerted on a surface. It is defined as the force (F) applied perpendicular to the surface of an object, divided by the area (A) of that surface:
P=F/A .
Units of Pressure:
Pascal (Pa): The SI unit of pressure, where 1 Pascal equals 1 Newton per square meter (N/m²).
Types of Pressure:
Atmospheric Pressure: The pressure exerted by the weight of the atmosphere. At sea level, it is approximately 101,325 Pascals or 1 atmosphere. Atmospheric pressure decreases with altitude.
Gauge Pressure: The pressure relative to atmospheric pressure. Gauge pressure can be positive or negative depending on whether it is above or below atmospheric pressure.
Absolute Pressure: The total pressure including atmospheric pressure. It is measured relative to a perfect vacuum and is always positive.
Applications and Importance:
Fluid Mechanics: In fluids, pressure differences drive the flow of liquids and gases. For instance, water flows from high to low
pressure areas, and this principle is used in various applications such as pumps and hydraulic systems.
Engineering and Design: Engineers must consider pressure when designing structures like bridges and dams to ensure they can withstand forces and avoid failure. Pressure also plays a critical role in the design of pressure vessels and pipelines.
Medicine: Blood pressure, the pressure exerted by circulating blood on the walls of blood vessels, is a crucial health indicator. Devices like sphygmomanometers measure blood pressure.
Meteorology: Atmospheric pressure readings are used in weather forecasting. Changes in atmospheric pressure can indicate upcoming weather changes.
Pressure Measurement:
Various instruments are used to measure pressure, including:
Barometers: Measure atmospheric pressure.
Manometers: Measure gauge pressure in fluids.
Pressure Sensors: Electronic devices used in various industries to monitor and control pressure.
Concepts Related to Pressure:
Boyle’s Law: In a closed system at constant temperature, the pressure of a gas is inversely proportional to its volume.
Hydraulic Systems: Use the principle of pressure transmission to lift or move heavy objects using fluids.
Understanding pressure and its effects is essential across many fields, from industrial applications to everyday life.
Ploughing tractors have very wide tyres.Explain why?
A Box of mass 720kg is placed on a table.if the area of contact in the table is 1.8m2.calculate pressure it exerts on table.
A Women wearing shoes with sharp pointed heels exerts more pressure than an elephant.why?
A Student placed his thumb firmly on the outlet of a bicycle pump,to stop the air coming out.what happens to the pressure and the volume of the trapped air as the pump handle is pushed in.