The velocity-displacement graph describing the motion of a bicycle...

For $0 \le x \le 200$

$v = mx + C$

$v = \dfrac{1}{5}x + 10$

$a = \dfrac{vdv}{dx} = \left(\dfrac{x}{5} + 10\right)\left(\dfrac{1}{5}\right)$

$a = \dfrac{x}{25} + 2 ⇒$ Straight line till $x = 200$

for $x > 200$

$v =$ constant

$⇒ a = 0$