A body is said to be in motion when its position changes continuously with respect to a stationary body taken as a reference point.
DISTANCE AND DISPLACEMENT
|Distance and Displacement Examples|
The distance covered by a body is the actual length of the path traveled by the body between the initial position and final position.
The displacement of a particle is the change in position of the particle in a particle in a particular direction and is given by a vector drawn from its initial position to its final position.
In fig,(a), AB is the displacement and (AC+CD+DE+EB) is the distance traveled.
Also in Fig.(b), AC is displacement and distance covered is (AB+BC).
It is the distance moved by a moving body in unit time. Its unit is m/s or km/h.
where,S=speed, D=distance, t=time taken
An object is said to be moving with a uniform speed, if it covers equal distances in equal intervals of time.
an object is said to be moving with a variable speed, if it covers equal distances in unequal intervals of time or unequal distances in equal intervals of time.
Average speed for a motion is the ration of the total distance travelled by the object to the total time taken.
If the body covers equal distance with different speeds then
It is the rate with which a body moves in a particular direction. It is a vector quantity.
A body is said to be moving with uniform velocity,if equal displacements of the body take place in same direction in equal intervals of time.
If a body moves in such away that its speed or the direction or both changes with time,the body is said to have variable velocity.
Average velocity of a body is defined as the net displacement divided by the time taken for displacement.
as net displacement =X2-X1 and time taken = t2-t1
The rate of change of position of a body with reference to moving observer is regarded as the relative velocity of body w.r.t. observer when the two are moving in same direction, then relative velocity =v1-v2 .When the two are moving in opposite directions, then relative velocity = v1+v2.