BRAINCAKEQuantities and Units
Revision notes for Quantities and Units in OCR Physics A (H156). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Physical Quantities.Physics is about modelling the behaviour of objects by looking at their physical quantities.
- SI Base Units.Scientists all over the world use the same system of units, called SI units.
- Prefixes.The following prefixes signify orders of magnitude of the units in base 10.
- Derived Quantities and Units.All other quantities are derived quantities and derived units and can be derived from the seven base quantities and units.
- Scalar Quantities.A scalar quantity has magnitude (size) only and no direction.
- Vector Quantities.A vector quantity is a quantity that has both magnitude(size) and direction.
- Adding Perpendicular Vectors.If two vector quantities act from the same point and are perpendicular to each other, there are two ways to add them and find the resultant of the…
- Resolving Vectors into two Components.Vectors can be resolved or separated into their vertical or horizontal components or any two components at right angles to each other. using…
- Adding Non-Perpendicular VectorsYou can add two vectors that are not perpendicular using the Cosine Rule.
- Subtracting VectorsSubtracting vectors gives the change or the difference.