DISTANCE AND DISPLACEMENT

Hi Friends here we come again with the previous point that is related to Motion. In previous Post we have talk about Motion where we have dealt with some points so now lets continue from there...  

                        DISTANCE AND DISPLACEMENT

Distance:-The length of the actual path between the initial and final position of the particle is called the distance.

Another word we can say that: The term distance actually is the distance travelled by a moving body.

Unit of distance

Distance can be expressed in any suitable unit of length, eg., centimeter, meter, kilometer, etc. The SI unit of distance is meter (m). In CGS system, the unit of distance is centimeter.

For example, if a person moves from A to B (1 km), B to C (1 km) and then from C to D (1.5 km), then the total path length (distance) covered by the person is given by,

Distance travelled = AB + BC + CD

                             = 1 km + 1 km + 1.5 km = 3.5 km

So, the distance travelled by a body is a scalar quantity.

Displacement: The displacement of a particle is defined as the change in position of the particle in a particular direction and is given by a vector drawn from its initial position to its final position.

Another word we can say that: The shortest distance between the initial and the final positions of a moving body is called its displacement.

Unit of displacement: Displacement can be expressed in any suitable unit of length, eg., centimeter, meter, kilometer, etc. The SI unit of displacement is meter (m). In CGS system, the unit of displacement is centimeter.

⋴∆∆∆Ex: Consider a body moving in a particular direction along a straight line. Let it cover a distance x1 in time t1 and x2 in time t2 from the start.

Then, the displacement during the time interval (t2 - t1) is,

                    Displacement = (Final position) – (Initial position)

   Or,                             d = (x2 – x1)

Characteristics of displacement: The displacement of a body has the following characteristics:-

• Displacement is a vector quantity. So, displacement has magnitude as well as direction.
• The displacement of a body is for a certain interval of time.
• The displacement of a body may have a positive, zero or a negative value.

  Distance and Displacement

Distance is the actual path length covered by a moving particle or body in a given time interval, while displacement is the change in position vector, i.e., a vector joining to final positions. If a particle moves from A to C through a path ABC. Then distance (∆s) Travelled is the actual path length ABC, while the displacement is

If a particle moves in a staight line without change in direction, the magnitude of  displacement is equal to the dostamce travelled, otherwise, it is alwyas less than it. Thus,

                            |Displacement| ≤ Distance

Thank you(Sashi Kant)