Question

The speed of an object is always positive whereas the velocity of an object can be positive or negative.explain.

Answer 1

The speed of an object is always positive where as the velocity of an object can be positive or negative because the speed is a scale quantity it will always be positive because it don't have sense of direction and velocity is a vector quantity , it has sense of direction...
The circular motion is an example.....

Answer 2

speed = distance/ time ...and distance is a scalar quantity and is always positive., while
velocity = displacement / time..and displacement is a vector quantity and it canbe positive or negativ.. that's why the speed of an object is always positive whereas the velocity can be positive or negative.