Velocity is a scalar quanitity.So when direction changes it also changes.Sometime the magnitude may be equal.But the signs are different.In uniform motion ,an object travels in the same direction and covers equal distance in equal intervals of time.Therefore velocity is equal.(what''s velocity ?Displacement/Unit time).Also what''s avg velocity?It''s some velocity with which you should go in equal intervals of time to get a destination in a particular time so that you can get the destination without hurry.(got the idea?)

So in this case you are going in same direction with equal displacement/unit time.So naturally this becomes avg velcoity.

Have a nice day.:

UNIFORM MOTION MEANS MOTION IN A STAIGHT LINE

 WHEN YOU TRAVEL IN A STRAIGHT LINE AVERAGE VELOCITY= TOTAL DISPLACEMENT/TOTAL TIME

AND VELOCITY IS =DISPLACEMENT/TIME

IN MOTION IN A STRAIGHT LINE TOTAL DISPLACEMENT AND DISPLACEMENT IS SAME MEANS AVERAGE VELOCITY AND VELOCITY IS SAME AT ANY INSTANT

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VELOCITY IS CONSTANT

DEAR FREIND. :)

This could be explained by giving a example, suppose you, on a motorbike planned to travel 1km on a straight road.

suppose you are asked to travel that 1km in 60 sec or 1 minute.

considering following two cases.

CASE I  : There are no obstacles on road.
             you''ll straight forward start your bike and will cover that kilometer with a constant speed of 60km/h.
             this meant you performed a uniform motion.

CASE II :OBSTACLES ON ROAD.

             suppose there is traffic on road, so you''ll have to apply breaks many times during that journey but you have given

             a deadline of 60 sec, but apllying breaks will decrease you velocity ofcourse, so you''ll have to cover that lost speed

             by speeding up more when you get space. 

There if you managed to get there in 60 sec, this meant wherever you varied speed in between, you managed to cover 1 km in 60 sec. same as in case 1, therefore here your average velocity will be 

V_AV=   Total distance covered / total time taken.=60 km/h

in case 1 also you covered 1 km in 60 sec, therfore giving average velocity of 60km/h
but unlike case 2 , you were travelling at 60 km/h at all times. 

WHEN A BODY IS PERFORMING UNIFORM MOTION ITS VELOCITY IS SAME AS AVERAGE VELOCITY AT ALL INSTANTS.

fORMALLY

Commonly , Instant velocity is reffered as Velocity, which means the velocity of any object with respect to non accelerating reference frame, at any intance of time.
i.e Velocity of object at a particular time, say t^th second.

Where as AVERAGE VELOCITY is the mean of all velocities attained by a body during a time interval, say ''t'' seconds. i.e total distance covered in ''t'' seconds. Which doesn''t say any thing about what was the velocity during the time interval.

IF a body is performing uniform motion, it''s velocity doesn''t vary at any intant during that time interval, therfore average velocity is eqaual to instant velocity at all times.


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uniform motion means equal distances covered in equal interval of time.

average velocity = total displacement/total time taken

now,when a particale is in uniform motion and

consider it covers x distance t time

velocity=x/t

then to cover next x distance it will again take t time

and so on,

now consider it covers nx distance,it will take nt time

then average velocity= nx/nt

=x/t

that is equal to its velocity that is x/t