How many feet will it take a car traveling at 120 mph to stop?
We need to know the breaking force and the mass to get the negative acceleration or know the acceleration itself.
To calculate the stopping distance of a car, we need to consider various factors such as reaction time, braking efficiency, and road conditions. However, I can provide you with a general estimate based on an average car.
First, let's convert the speed from miles per hour (mph) to feet per second (fps). Since 1 mile = 5,280 feet and 1 hour = 3,600 seconds, we can calculate:
120 mph * (5,280 feet / 1 mile) * (1 hour / 3,600 seconds) = approximately 176 fps
Now, the stopping distance of a car can be determined using the following formula:
Stopping Distance = Reaction Distance + Braking Distance
1. Reaction Distance: This is the distance covered by the car during the driver's reaction time. It usually depends on various factors like attention level, alertness, and condition of the driver. As an average estimate, we consider 0.5 seconds for reaction time.
The formula for reaction distance is:
Reaction Distance = Speed * Reaction Time
Reaction Distance = 176 fps * 0.5 seconds = 88 feet
2. Braking Distance: This is the distance the car takes to come to a complete stop from the calculated speed. Braking distance depends on factors such as the car's braking system, tire conditions, road surface, and weather conditions. For the purpose of estimation, we assume a braking efficiency of 100%.
Although it may vary, a common rule of thumb is that the braking distance for a passenger car traveling at a constant speed on dry pavement is approximately the same as the reaction distance. Therefore, the estimation for braking distance is also 88 feet.
Finally, we can calculate the total stopping distance:
Stopping Distance = Reaction Distance + Braking Distance = 88 feet + 88 feet = 176 feet
Therefore, for an average car traveling at 120 mph, it would take approximately 176 feet to stop. Keep in mind that this is a rough estimate, and the actual stopping distance may vary depending on various factors.