Quantities and units in mechanics
AS level
- Understand and use fundamental quantities and units in the S.I. system: length, time, mass
- Understand and use derived quantities and units: velocity, acceleration, force, weight
A level
- Moments
The meaning of force
This is a link to the Physics Classroom. It explains how the Newton as a unit of force is derived from acceleration in S.I. units.
International System of Units (SI)
This is a link to the American site National Institute of Standards and Technology.
The SI base units are defined and there is also information about their historical context. Be aware of the spelling used for the length "metre".
SI Brochure
This is a link to "Bureau International des Poids et Mesures".
Chapter 2 defines the base units including mass length and time and the derived units including velocity and acceleration.