a) From `t = 0` to `2`, the acceleration was `a=(Deltav)/(Deltat)=3/2=1.5\ text(ms)^-2`

From `t = 2` to `5`, the acceleration was `0\ "ms"^-1`.

The body was neither speeding up nor slowing down.

From `t = 5` to `8`, the acceleration was `a=(Deltav)/(Deltat)=(-3)/3=-1\ text(ms)^-2`

The body was slowing down, so the acceleration was negative.


b) The distance travelled is the area of the trapezoid (trapezium).

`text(distance)` `=((a+b)h)/2` `=((8+3)(3))/2=16.5\ text(m)`


c) `text(average speed)=text(distance travelled)/text(time taken)`

`=16.5/8`

`=2.1\ text(ms)^-1`

Easy to understand math videos:
MathTutorDVD.com