Velocity and Speed
The average velocity `v_(x,avg)` of a particle is defined as the particle’s `displacement` `∆x` divided by the time interval `∆t` during which that displacement occurs:
`v_(x,avg)=(∆x)/(∆t)`
The average speed `v_(avg)` of a particle, a scalar quantity, is defined as the total distance d traveled divided by the total time interval required to travel that distance:
`v_(avg)=d/(∆t)`
From Example 1:
Average velocity of the car from A to F:
`∆x = -53 m - 30 m = -83 m`
`∆t = 50s-0s = 50s`
`v_(x,avg)=(∆x)/(∆t)=(-83m)/(50s) = -1.7 m//s`
Average speed of the car from A to F:
`d_(a->f) = 127 m`
`∆t = 50s-0s = 50s`
`v_(avg)=d_(a->f)/(∆t)=(127m)/(50s) = 2.5 m//s`