The graph below shows the toy car's motion as a function of time and distance. After how many seconds does the car change its speed?

• We can see that a continuous straight line is shown in the graph till 12 seconds. This implies that the speed of the car is constant till 12 seconds.
• However, after 12 seconds, the line shown in the graph is more inclined towards the x-axis. It implies that the car now covers less distance in the given time interval which means the speed of the car decreases.

Therefore, we can say that the speed of the car changed after 12 seconds.