A toy car with charge q moves on a frictionless horizontal plane...

$0 < t \le 1s$ ~velocity increases from $\text{0}$ to $\text{6 m/s}$

$1s \le t \le 2s$ : velocity decreases from~ $\text{6 m/s}$ to~$\text{0 m/s}$

But car continues to move forward and then it reverses its direction at~$t = 2s$ and after $\text{2 s}$ accelerates backward



Distance undefined

$| \dfrac{1}{2} \times 6 \times 2 | + | \dfrac{1}{2} \times ( - 6 ) \times 1 |$

$= 6 + 3$

$= 9m$

Displacement = Total area under $\text{v} - t$ graph

$= 6 - 3 = 3m$

$∴$ Average velocity $= \dfrac{Displacement}{Time} = \dfrac{3}{3} = 1m/s$

$∴$ Average speed $= \dfrac{Totaldistance}{Time} = \dfrac{9}{3} = 3m/s$