Kilopascal
Pascal or kilopascal is a derived unit of pressure. In physics units and conversion of units is an important part of the learning. Kilopascals are shortened or abbreviated to kPa with a lower case k, an uppercase P and a lowercase a. Kilo means one thousand hence there are one thousand Pascals in a kilopascal. The pascal (a symbol used is Pa) is the SI derived unit of pressure or stress (also for modulus of elasticity like Young's modulus and tensile strength).
The unit of the pressure of the pascal is equivalent to one newton per square metre (N/m2). In our day to day life, the pascal is most frequently used in the form of kilopascal (1 kPa = 1000 Pa). One kilopascal corresponds to about 1% of atmospheric pressure with reference to the sea level.
kPa
The conversion of units is an important concept in physics. We know that a pascal is a derived unit of pressure. Pressure is defined as the normal force exerted by a fluid per unit area. The concept of pressure is used mainly while discussing liquids and gases. The counterpart of the pressure in solids is normal stress. Now lets us have a look at how a pascal is derived.
According to the definition of the pressure we have,
⇒ Pressure = \[\frac{Force}{Area}\] = \[\frac{N}{m^{2}}\] ………..(1)
Force is expressed in Newton’s and the area on which the force F exerted is expressed in m2.Therefore pressure is expressed in terms of N/m2known as the Pascal in general.
Therefore We Write,
1 Pascal = Newton meter-2 =1 Nm-2…….(2)
The unit of pressure pascal is too small for most of the pressures encountered in our everyday lives. Therefore we use multiples of pascals such as kilopascal, megapascal etc….
In kilopascal, we will be having one thousand Pascals. We know, a kilo is an abbreviated form of 1000. Similarly in megapascal, we will be having 106pascals. Mathematically we write,
⇒1 k Pa=103 Nm-2= 1000 Nm-2
And,
⇒1 M Pa = 106 Nm-2
Kilopascal To Psi
The pressure can also be measured in terms of Psi, bar. Therefore we can have unit conversions such as the conversion of Kilopascal to Psi, pascal to Psi, Psi to the bar, Psi to kPa, etc. Let us have a look at the conversion of kilopascal to Psi (pound squared inch). In the English system, the pressure is measured in terms of the Pound force per square inch which is abbreviated as Psi in general. One atmospheric pressure is equal to 14.696 Psi.
Now, the relation between kilopascal and Psi is given by the formula:
⇒k Pa= 0.145 Psi and 101.325 kPa=14.7 Psi
Similarly, we can write,
⇒1Psi = 6.89 kPa
This is the required formula for converting kilopascal to Psi. These conversion techniques can be mastered after having thorough practice and solving numerical. Let us have a look at a few numerical problems for better understanding.
Examples
1. Convert 130 Kilopascal to Psi.
Sol: Given, we have a pressure exerted by some fluid or gas is 130 kPa. We are asked to determine 130 kPa in terms of the Psi.
We know that,
⇒1 k Pa= 0.145 Psi
Therefore, we write:
⇒130 k Pa=130x0.145 Psi=18.85 Psi
Thus, 130 kilopascal is equal to 18.85 Psi.
2. Convert 50 Psi to Kilopascal.
Sol: Given, we have a pressure exerted by some fluid or gas is 50 Psi. We are asked to determine 50 Psi in terms of the kPa.
We know that,
⇒1Psi = 6.89 kPa
Therefore, we write:
⇒1Psi = 6.89 kPa
⇒50 Psi = 50 x 6.89 kPa=344.5 kPa
Thus, 50 Psi is equal to 344.5 kPa.
3. Convert 122 Kilopascal to Psi.
Sol: Given, we have a pressure exerted by some fluid or gas is 122 kPa. We are asked to determine 130 kPa in terms of the Psi.
We know that,
⇒1 k Pa= 0.145 Psi
Therefore, we write:
⇒122 k Pa=122 x 0.145 Psi=17.69 Psi
Thus, 122 kilopascal is equal to 17.69 Psi.
4. Convert 35 Psi to Kilopascal.
Sol: Given, we have a pressure exerted by some fluid or gas is 35 Psi. We are asked to determine 35 Psi in terms of the kPa.
We know that,
⇒1Psi = 6.89 kPa
Therefore, we write:
⇒1Psi = 6.89 kPa
⇒35 Psi = 35 x 6.89 kPa=241.15 kPa
Thus, 35 Psi is equal to the 241.15 kPa.
FAQs on Kilopascal - Unit of Measurement
1. What is a kilopascal (kPa)?
A kilopascal, abbreviated as kPa, is a unit used to measure pressure. It is a multiple of the Pascal (Pa), which is the standard SI unit for pressure. The prefix 'kilo' signifies one thousand, meaning that 1 kilopascal is exactly equal to 1,000 Pascals. It is commonly used because the Pascal is a very small unit for many practical applications.
2. How is the base unit, the Pascal (Pa), defined in physics?
The Pascal (Pa) is a derived SI unit. It is defined as the pressure resulting from a force of one Newton (N) applied perpendicularly to a surface area of one square metre (m²). Therefore, the fundamental formula is 1 Pa = 1 N/m². This unit is named after the French physicist Blaise Pascal.
3. What kind of phenomena are typically measured using kilopascals?
Kilopascals are used to measure a wide range of pressures in scientific and real-world contexts. Common examples include:
- Atmospheric pressure: Weather reports often state barometric pressure in kPa.
- Tire pressure: Vehicle tire pressure is frequently specified in kPa in many countries.
- Fluid dynamics: It is used to measure pressure in liquid and gas systems.
- Material science: For quantifying stress and tensile strength, though Megapascals (MPa) are also common.
4. How do you convert kilopascals (kPa) to other common pressure units like psi?
To convert between kilopascals (kPa) and Pounds per Square Inch (psi), you can use specific conversion factors. The approximate relationships are:
- To convert from kPa to psi: 1 kPa ≈ 0.145 psi. So, you multiply the kPa value by 0.145.
- To convert from psi to kPa: 1 psi ≈ 6.895 kPa. You would multiply the psi value by 6.895 to get the equivalent pressure in kilopascals.
5. Why is the kilopascal (kPa) often preferred over the pascal (Pa) for everyday measurements?
The kilopascal is preferred in many practical applications because the pascal (Pa) represents a very small amount of pressure. Using pascals for common measurements, like atmospheric pressure (approx. 101,325 Pa), results in large and cumbersome numbers. The kilopascal (101.325 kPa) provides a more convenient and relatable scale for these magnitudes, making values easier to read, communicate, and understand.
6. What is the relationship between atmospheric pressure at sea level and the kilopascal?
Standard atmospheric pressure at sea level is a universal benchmark. It is defined as 101.325 kilopascals (kPa). This value, often rounded to 101.3 kPa or simply 100 kPa for general calculations, serves as a standard reference point (1 atm) in many fields of science and engineering, including chemistry and meteorology.
7. Are kilopascals (kPa) and kilonewtons per square metre (kN/m²) the same thing?
Yes, they are dimensionally and numerically the same. Since 1 Pascal (Pa) is defined as 1 Newton per square metre (N/m²), it follows that 1 kilopascal (1,000 Pa) is equal to 1,000 Newtons per square metre. This can be expressed as 1 kiloNewton (kN) per square metre (m²). Therefore, 1 kPa = 1 kN/m².
8. How does the concept of pressure in kPa differ from stress in solids?
While both pressure and stress are defined as force per unit area (and share the same units like Pa or kPa), their context is different. Pressure is a term typically used for fluids (liquids and gases) and is a scalar quantity that describes the perpendicular force a fluid exerts on a surface. In contrast, stress is used for solids and is a tensor quantity that describes the internal forces within the material, which can be compressive, tensile (pulling apart), or shear (sliding).
