This interactive 3D physics simulation models a boat traveling in a straight buoy-marked channel. The boat first moves at constant speed. When the driver reaches the braking point, a floating log is a specified distance ahead, so the boat must decelerate rather than turn away.
During the braking part of the motion, the boat slows uniformly from its initial speed to rest in the selected braking time:
Therefore, the braking acceleration is:
The stopping distance is the average speed multiplied by the braking time:
The first part of the animation separates uniform motion from accelerated motion. The displayed braking distance and time begin when the boat starts decelerating.
When acceleration is opposite the boat's velocity, the boat slows down. A negative acceleration does not automatically mean an object is slowing down; the velocity direction must also be considered.
Compare the calculated stopping distance with the available distance to the log. If the stopping distance is smaller, the boat stops with water still remaining between it and the log.
Suppose a boat begins braking at 10 m/s, the log is 30 m ahead, and the braking time is 4.0 s.
The stopping distance is:
The boat therefore stops 10 m before the log.