Final answer:
The concept being described is known as following distance and is used to maintain a safe space between cars. The calculations for how far a car travels depend on its speed and the time, with an example given for a car traveling at 12 m/s over 10 seconds, which would travel 120 metres. Safe crossing guidelines involve using the following distance rule but should always be contextual.
Step-by-step explanation:
The term used to describe one car length for each 10 miles per hour is known as following distance. This is a rule of thumb used by drivers to maintain a safe distance from the vehicle in front to ensure enough time to react and stop if necessary. The idea is to keep at least one car length between you and the car in front for every 10 mph of speed.
As for the calculations, if a car is traveling at a speed limit represented in metres per second (m/s), and you walk with a speed represented in metres per second (m/s), to find out how many metres the car travels while you walk the width of a car, which is a much smaller distance, you would use the formula distance = speed × time. Given that a car is traveling at 12 m/s and you find the time it takes to walk the width of a car, let's say 10 seconds, the car would have traveled 12 m/s × 10 s, which equals 120 metres.
As per the reference information, if we are talking about average speed, this is calculated by dividing the total distance traveled by the time taken for the trip. If a rabbit is running at 10 km/h, its speed in metres per second would be 10 × 1000 / 3600, which equals approximately 2.78 m/s.
When considering how safe it is to cross a street, one should observe the approaching cars and ensure they are a sufficient following distance away, which may vary depending on the speed limit and other situational factors. A general rule of thumb might be to wait for the cars to be several car lengths away, with each car length corresponding to the 10 mph per car length rule, but judgement should be based on actual conditions and safety considerations.