A car is moving along a straight (OP). It moves from `O to P` in `18 seconds` amd retuns from `P to Q` in 6 seconds`, where `OP=360 m` and `OQ=240 m What are the car the average velcoty and average speed of the car in going (a) from `Oto P` and back to `Q` ?

Explanation

(i) Average velocity `=("Total displacement")/("Total time interval")`
`v_(av)=(+360)/(18s)=+20 ms^(-1)`
Average speed `=("Path length")/("Time interval")=(360m)/(18s)=20 ms^(-1)`
Thus, in this case, the average speed is equal to the magnitude of the average velocity.
(ii) In this case,
Average velocity `=("Total displacement")/("Total time")=(+240 m)/((18+6.0)s)`
`=+10 ms^(-1)`
Average speed `=("Path length")/("Time interval")=(OP+PQ)/(Delta t)`
`=((360+120)m)/(24 s)=20 ms^(-1)`