Orders of Magnitude
Expressing numbers using powers of ten to represent a range of magnitudes in physics.
Uncertainties
Estimates of the difference between a measurement reading and the true value, caused by random or systemic errors.
Types of Uncertainties
Absolute uncertainty (fixed quantity), fractional uncertainty (fraction of total measurement), percentage uncertainty (percentage of total measurement).
Combining Uncertainties
Addition/subtraction (sum of absolute uncertainties), multiplication/division (sum of fractional uncertainties), power (magnitude of n times fractional uncertainty).
Scalars and Vectors
Scalars have magnitude, vectors have magnitude and direction. Distance is scalar, displacement is vector.
Vectors Representation
Vectors are represented by arrows, where the arrowhead shows direction and length indicates magnitude.
Combining Vectors
Combine vectors head to tail and use Pythagoras’ Theorem to find the resultant magnitude.
Error Bars
Represent uncertainty in measurements on graphs with vertical and horizontal bars at each point.
Lines of Best-Fit
Drawn to minimize distance between points and the line, with some points above and some below.
Uncertainty in Gradient
Calculated as ΔK = (kmax - kmin)/2, where k is the gradient and ΔK is the uncertainty in the gradient.