position and movement物理題

"Scalar" is a physical quantity that has only magnitude. Examples are mass, density, volume, temperature, energy, time, frequency ...... etc.
"Vector" is a physical quantity that has both magnitude and direction. Examples are velocity, displacement, acceleration, momentum, force .... etc
Distance is a scalar, because it indicates only the actual length of path that have been travelled.
Displacement, on the other hand, is a vector. It gives not only the distance travelled, but the direction as well. Hence, a displacement of 10 km to the east is different from a displacement of 10 km to the west, because the directions of travel are different.