A derived quantity is a physical quantity that is defined in terms of other fundamental physical quantities. In other words, it's a quantity that is calculated using a formula that involves other, more basic quantities.
Think of it like this: you can't directly measure things like speed or volume, but you can calculate them using measurements of other quantities.
For example, speed is derived from the fundamental quantities distance and time. You calculate speed by dividing the distance traveled by the time taken.
Examples of Derived Quantities:
- Speed: Derived from distance and time.
- Volume: Derived from length, width, and height.
- Density: Derived from mass and volume.
- Acceleration: Derived from velocity and time.
- Force: Derived from mass and acceleration.
- Energy: Derived from force and distance.
- Power: Derived from energy and time.
Key Characteristics of Derived Quantities:
- Defined by a formula: Derived quantities are calculated using a formula that involves other fundamental quantities.
- Units derived from base units: The units of a derived quantity are derived from the units of the fundamental quantities that it is based on. For example, speed is measured in meters per second (m/s), which is derived from the units of distance (meter) and time (second).
- Can be expressed in different units: Depending on the context, a derived quantity can be expressed in different units. For example, speed can be measured in kilometers per hour (km/h) or miles per hour (mph).
Practical Insights:
- Derived quantities are essential for understanding and describing the physical world.
- They allow us to relate different physical quantities to each other.
- They provide a framework for making calculations and predictions about physical phenomena.
