Question

An object travels North at `7 m/s` for `6 s` and then travels South at `3 m/s` for `8 s`. What are the object's average speed and velocity?

Answer 1

Speed=`33/7m/s`and velocity `=9/7m/s`

Explanation:

Distance traveled due North in 6s @ `7m/s` is =`7xx6=42m`
Distance traveled due South in 8s @ `3m/s` is =`3xx8=24m`
Total Distance traveled `=42m+24m=66m`
Total time taken = `6+8=14s`
So average speed `=(Total Distance )/( time)=66/14m/s=33/7m/s`

Now net displacement due North=`42-24=18m` (North,South being oppositely directed)

Hence Average velocity due North`=(Displacement )/(Time)=18/14m/s=9/7m/s`