Final answer:
At 100 mph, you should keep a distance of approximately 27.5 car lengths between you and the car in front for safety, as calculated by the three-second rule and the speed converted to feet per second.
Step-by-step explanation:
The distance you should keep from the car in front of you while driving is often based on the concept called the 'three-second rule.' This rule states that you should be able to count to three from the point the car in front of you passes a stationary object until you pass the same object. At higher speeds, like 100 miles per hour (mph), you would need to increase that distance to ensure you have enough time to react to sudden changes.
To calculate the exact distance in car lengths, we first convert the speed to feet per second (fps) because we know the car length in feet. One mile is 5280 feet, and there are 3600 seconds in an hour, so:
100 mph = 100 × (5280 feet) / (3600 seconds) = 146.67 fps.
Next, using the three-second rule, the following distance at 100 mph:
3 seconds × 146.67 fps = 440 feet.
Since an average car is about 16 feet long, we divide 440 feet by 16 feet to get the number of car lengths:
440 feet / 16 feet/car = 27.5 car lengths.
Therefore, at 100 mph, you should keep a distance of approximately 27.5 car lengths between you and the car in front of you.