Tanusri Gururaj, Academic content writer of Physics at Edumarz
The motion of any object is described using the following terms-
Distance: It is the length of the path covered by an object. It is a scalar quantity and hence, it has magnitude but no direction.
Displacement: It is the shortest distance between the initial and final points. It has both magnitude and direction since it is a vector quantity.
Speed: It is defined as the distance that an object travels per unit of time.
Velocity: It is the distance travelled in a given direction per unit of time.
Acceleration: The measure of how fast the velocity of an object changes.
Time: The duration of any particular event.
Understanding distance and displacement with an example-
Consider this example of a triangular path.
Let us assume that a person goes from path A to B and then from B to C.
The distance is the length of the actual path covered by the person that is AB + BC.
The displacement is the shortest distance between the initial and final points and hence will be AC.
Understanding speed and velocity with an example-
52 km/hr is the speed of a truck ‘A’ on a highway, whereas 52 km/hr east is the velocity of a truck ‘B.’
The explanation behind this is that in the case of truck ‘B,’ 52 km/hr east gives both magnitude and direction, where 52 km/hr is the magnitude and east is the direction.
Formulae related to this concept-
Speed = distance/time
Unit = m/s
Velocity = displacement/time
Unit = m/s
Acceleration = Change in velocity of the object/time taken for the velocity change
Change in velocity = final velocity of object – initial velocity of object
Unit = m/s2
The object undergoing uniform motion covers equal distances in equal intervals of time.
For example, a car covers 20m in the first second, the next 20m in the next second, and so on.
In this type of motion, the particular object travels unequal distances in equal intervals of time.
For example, a car covers 1km in the first 35 seconds, 0.9km in the next 35 seconds.