The speed limit near a school is 30km/h but Joe Cool thinks he can ignore it. He is driving at 60km/h. To make matters worse, he is talking on his cell phone. Suddenly a child rides his bicycle out of school grounds and across the road on the pedestrian crossing. The maximum rate at which Joe can slow down is 8m/s squared. How far away from the child must Joe be when he first sees the child? (before he applies the brakes) in order to stop in time.

Thanks

1 answer

v^2 = 2ax.
You'll have to turn the kph into m/s as well.