Question

A particle moves in a circle with O as centre and AO=OB = 5 CM as radius. it starts from A . Calculate
a) the distance covered
b0 the displacement when it reaches B.

Answer 1

displacement  = 5√2 

distance = the curcumfreence of the circle 

but I can't answer without figure 
= 

Answer 2

Case I )
calculate distance :
Let θ  be the angle subtended between radii OA and OB.
Distance will be the total path covered between two points AB.
Distance=length of minor Arc AB = radius x θ
                                            =5xθ=5θ

Case ii)
Calculate displacement :
As the displacement would be the shortest path between source and destination.
Displacement = Length of the chord AB.
                       =2r sin(θ/2)
                       =2x5(sinθ/2)
                      =10 sin(θ/2)