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# Difference between fundamental quantities and derived quantities of Physics.

by Guest315  |  earlier

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I have question related to the subject of Physics. I have heard a lot about the fundamental and derived quantities in physics and I would like to know that how these two types of quantities can be defined as well as their difference.

1. Harry

Scientists use all sorts of units of measurements to get values and quantities. Some of these are called fundamental quantities and some of them are called derived values. Fundamental quantities are those which do not depend on other quantities like temperature, mass and length. Derived quantities are those which depend on fundamental quantities which include force, volume and density. Fundamental quantities are the base units in a given measurement system. They can also be directly measured. These types of values have something in common. They can all be directly measured, like we can measure distance travelled, time taken, volume as well as temperature. While fundamental quantities can be directly measured, derived ones must be calculated. They are calculated from the base unit. That's the biggest difference. Examples of derived quantities include:
1. Speed. You might be able to see your speed on the speedometer on your car, but it is a derived value. Speed is calculated by dividing total distance traveled by the time it took to travel it
2. Celsius and Fahrenheit. Zero degrees Celsius is 273.15 Kelvin. Zero degrees Fahrenheit is 255.37 Kelvin. Kelvin is the base unit in the SI system. However, it is much easier to measure Celsius and Fahrenheit, but they are still considered to be derived.
3. Watts. That is a 100 Watt light bulb. Watts are power, otherwise known as radiant flux. It's the amount of all the light including infrared, ultraviolet, and visible. Watts are calculated by dividing the Joules by seconds, so a Watt is a J/s.
4. Joules. Joules are also a derived quantity and a Joule is the amount of energy it takes to exert 1 Newton of force for one meter. Joules are an amount of energy. Another unit for measuring energy, more common in the non-scientific world, is the calorie. A calorie is the amount of energy required to raise the temperature of one milliliter of water one degree Celsius at standard temperature and pressure. The calories listed on the back of food packages are actually Kilo-calories.
5. Newton. A newton is also a derived value which is the net force required to accelerate one kilogram of matter one meter per second. A meter is the fundamental distance in the SI system, and a second is the base unit of time. A kilogram is still a derived quantity.
6. Kilogram. Mass, when measured in grams, is a fundamental quantity. Kilograms, however, are one thousand grams, so kilograms are derived.

2. Guest5918833
Fundamental quantities can be considered to be dimensions, but in a loose context. In physics, when we refer to dimensions, we usually refer to space and time and not the dimension of the luminosity

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