The displacement-time graphs of two bodies P and Q are represented by OA and BC respectively. What is the ratio of the velocity of P and Q ? `angleOBC=60^(@)` and `angleAOC=30^(@)`

Explanation

Velocity, v `=(ds)/(dt)= tan theta`= slope of the displacement -time graph where `theta` = angle made with the time axis.
`:. v_(P)/v_(Q)=(tantheta_(P))/(tantheta_(Q))=(tan30^(@))/(tan(-30^(@)))=(tan30^(@))/(-tan30^(@))=((1)/sqrt3)/(-(1)/sqrt(3))=-(1)/(1)`
So the ratio is `1:(-1)`.