Vectors & Relative Velocity / Chapter activities
Vector equations use component notation; x and y identify directions, and A/B identifies the observer.
A vector has both. Displacement, velocity, acceleration and force are vectors. Speed is the magnitude of velocity.
Use i for initial and f for final, matching the initial / final convention used in the other chapters.
Changing direction changes velocity even when speed stays constant.
“A relative to B” means the velocity of A as measured by B. G denotes the ground.
+x = east / right; +y = north / up the page. Angles are measured anticlockwise from +x unless a bearing or named reference direction is explicitly requested.
For launch or initial velocities use vi,x and vi,y. For force components use Fₓ and Fᵧ. The direction of a zero vector is undefined.
A sloping vector can be resolved into perpendicular x and y components. The three arrows show one vector in three equivalent parts; this is not a motion path.
Equal scales on x and y. Diagram auto-fits; compare labelled values, not arrow lengths between different trials.
Only River crossing uses a motion animation. The boat moves with the ground-resultant velocity.