Math 2 Unit 1 Project: Full Stop Ahead
Period 3 Due: Friday, October 3, 2014
The formula d = 0.044s^2 + 1.1s gives you a safe stopping distance in d feet, where s is your speed in mi/h. Make a table of values for speeds 10, 20, 30, 40, 50, and 60 mi/h. Then, graph the function.
Why do you think the estimates of speed do not double when the skid marks double in length? Based on these results, what conclusions can you make about safe distances between cars?
The speeds do not double because the problem is demonstrating a quadratic equation. Since the product of the length of the skid marks and the numbers representing wet/dry roads are squared, there can never be a perfect half. Safe braking distances between cars vary on your speed and if the road is wet or dry. The faster you go and the wetter the road, the longer the skid mark.
Suppose you are driving on a dry road with 150 feet (about 10 car lengths) between your car and the car in front of you. Use the formula from Activity One to find the maximum speed you should be traveling in order to leave a safe stopping distance.
If you plug in 150 as d into the equation d = 0.044s^2 + 1.1s then the maximum speed you would need to drive is 47.21 mph.