Question

an artificial satellite moves around the earth with a velocity of constant magnitude, still its motion is said to be an accelerated

Answer 1

(1) In accelerated motion velocity of the object continuously changing.
In circular motion, direction of the object continuously changing i.e. its velocity keep on changing at each and every point hence motion will be same, where as magnitude i.e. speed of the body will remain same.
(2) satelite keeps changing its direction in a circular orbit at its every point, and if u recall the concept of acceleration it is associated with direction also .Thus if direction changes ,acceleration also changes inspite of constant velocity.

Hope it helps......