Distance, Displacement, Velocity, Speed and Acceleration

Distance and Displacement

Distance is the total path length traveled from one location to another. It is a scalar quantity.

Displacement is the distance between two locations measured along the shortest path connecting them, in specified location. It is a vector quantity. The SI unit of distance and displacement is metre (m).

Speed and Velocity

Speed is the distance traveled per unit time or the rate of change of distance.

Speed = total distance traveled / time taken

Velocity is the speed in a given direction or the rate of change of displacement.

Average velocity = displacement/ time taken

Acceleration and Deceleration

Acceleration is the rate of change of velocity.

Acceleration = change of velocity / time taken

Change of velocity = final velocity (v) – initial velocity (u)

Acceleration = (final velocity – initial velocity) / time taken
  = (v – u) / t

Things to remember:

1. Constant velocity means the object is not accelerating. Acceleration is zero.
2. Constant acceleration means the object is increasing its velocity.