Eduqo
General Science›Ch 1: Physics›Motion
Master distance, displacement, speed, velocity, and equations of motion for competitive exams.
Motion is the change in position of an object with time. Distance is a scalar quantity representing total path length, whereas displacement is a vector quantity representing the shortest straight-line distance between initial and final positions.
Memory Hooks
| Parameter | Distance | Displacement |
|---|---|---|
| Type | Scalar | Vector |
| Can it be zero? | Never (if moving) | Yes (can be zero) |
| Magnitude relation | Always >= Displacement | Always <= Distance |
Speed
(Rate of distance)
Rate of distance
A car moving at 60 km/h.
Velocity
(Speed with direction)
Speed with direction
Train moving North at 80 km/h.
Acceleration
(Rate of velocity change)
Rate of velocity change
Car speeding up from rest.
Retardation
(Negative acceleration)
Negative acceleration
Applying brakes on a cycle.
Displacement is always > distanceDistance is always >= displacement
Displacement can never exceed distance in magnitude; it is at most equal to distance.
Zero velocity means zero accelerationVelocity can be zero while acceleration is non-zero
At the highest point of a vertical throw, velocity is zero but acceleration due to gravity is 9.8 m/s².
Speed can be negativeSpeed is always positive or zero
Speed is a scalar quantity and cannot be negative, whereas velocity can be negative.
Q1.Which of the following physical quantities can be zero when an object is in motion?
Q2.A body starts from rest and moves with a uniform acceleration of 2 m/s² for 5 seconds. Find the distance traveled.