Question

a car covers a semi circular track of radius 5m with a constant speed of π m/s find the magnitude of of displacement nd average velocity

Answer 1

Displacement is the length of the shortest path between the final and initial positions which in this case, is equal to 2R = 10m.
Time taken to reach the other end of the semicircular track = Distance / Speed
                                                                                        = $\pi$R/ Speed
                                                                                        =  $\pi R/ \pi$
                                                                                        = R = 5 s
Average velocity = Total displacement / Total time taken 
                           = 10 / 5 = 2 m/s