Units

Definition

Units are standardized quantities used to measure physical quantities. They provide a reference for expressing and comparing measurements accurately.

5 Must Know Facts For Your Next Test

1. The International System of Units (SI) is the most widely used system of units in science.
2. There are seven base SI units: meter (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), and candela (cd).
3. Derived units are combinations of base units, such as meters per second ($\text{m/s}$) for velocity.
4. Dimensional analysis involves checking the consistency of units in equations to ensure they make sense physically.
5. Conversion factors allow you to convert between different units, such as inches to centimeters or pounds to kilograms.

Review Questions

• What is the primary purpose of using standardized units in physics?
• Name three examples of base SI units and their corresponding physical quantities.
• How do derived units differ from base units?

Related terms

Physical Quantity: A property that can be measured, such as length, mass, time, or temperature.

Dimensional Analysis: A method for checking the consistency of units in equations by ensuring that both sides have the same dimensions.

Conversion Factor: A ratio used to convert one unit of measurement into another.