Question

" the average velocity of a particle can be positive or negative but the average speed is always positive" prove the above statement.

Answer 1

See,
Here positive velocity means that the object is moving in the positive direction taking the cartesian system in mind when we plot the object in the distance time graph(slope gives the speed) or displacement time graph (slope gives velocity) we see the velocity is mostly positive because it is going with the y axis which means the object is moving forward in the case when the velocity is negative this means the object is going in the opposite direction which means the object is accelerating in the negative direction the speed whereas is a scalar quantity which does not tell us about the direction.
Speed will always be positive for example if we are going 20 my foeward we will still travel with the speed of 20 metre per second but even if we are going 20 metres backward the speed will still remain 20m/s the followings assumption is not true with the case of velocity because velocity tells us the direction as well as speed!
Hope it helped you!
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