1. Units, measurement and vectors, PHYS 101 at McGill
Ten exercises built on one idea: a physical quantity is never a bare number, and the direction is the part that cannot be added like one. Part A is the toolkit of the first two weeks, the SI base units and the conversion factor that has to be cubed, the significant figures a measurement actually earns, orders of magnitude and Fermi estimates, the components of a vector read off a right triangle, and the proof that two magnitudes of three and four add to anything between one and seven. Part B works at assessment level: three displacements summed component by component with the quadrant of the arctangent restored by hand, unit vectors and subtraction, five statements to correct, a laboratory density measured by water displacement with its percent uncertainty, and a ramp solved on tilted axes. No calculus anywhere, as the course demands: algebra, proportions and right triangle trigonometry only.