Even though the insect has crawled a total distance of 6 meters, its
displacement is 0 meters. During the course of the bug’s motion, it
covered 6 meters of ground (distance = 6 m). Yet, when it is finished, it
has not gone anywhere at all—there is no displacement for its motion
(displacement = 0 m). Displacement is a vector quantity and must
incorporate net direction. The 1 meter north is canceled by the 1 meter
south, and the 2 meters east is canceled by the 2 meters west.If we know that the displacement is horizontal, then it can be called ∆x; if the
displacement is vertical, then it’s ∆y. Displacement is a net change, so it may differ
in magnitude from total distance traveled (though if the path is all in one direction,
it will not). Since a distance is being measured, the SI unit for displacement is the
meter: [∆s] = m.
- A rock is thrown straight upward from the edge of a 30 m cliff,
rising 10 m then falling all the way down to the base of the cliff.
Find the rock’s displacement.