If a car is traveling at 55 mph in one direction, how long would it take to decelerate, turn around, and catch up with another car going at a steady speed of 100 mph in the opposite direction?

Opposite of what? If second car (100 mph) is going away from the first (55 mph), it will never catch up.

A long time

To determine the time it takes for the car traveling at 55 mph to catch up with another car going at 100 mph in the opposite direction, we need to consider a few factors.

First, let's assume that both cars start at the same point and travel on a straight road. When the car traveling at 55 mph decelerates, it will eventually come to a stop, turn around, and accelerate back up to its original speed of 55 mph in the opposite direction.

To find the time it takes for the car traveling at 55 mph to catch up with the other car, we can calculate the distance they need to cover relative to each other.

Let's define the distance between the cars when the decelerating car starts to turn around as "D". To catch up with the other car, the decelerating car needs to cover this distance while the other car moves in the opposite direction.

To calculate "D," we can use the equation: `D = (55 mph + 100 mph) × t`, where "t" is the time it takes for the cars to meet.

The combined speed of the cars is (55 mph + 100 mph) because they are moving in opposite directions and the total speed is the sum of their individual speeds.

Now, let's solve the equation for "t":

D = (55 mph + 100 mph) × t
D = 155 mph × t

Next, we need to consider the decelerating car's deceleration time and turnaround time.

Assuming the deceleration and acceleration times are negligible compared to the time it takes for the two cars to meet, we can consider the deceleration and turnaround as instant.

Therefore, the time it takes for the car traveling at 55 mph to catch up with the other car would be equal to `t = D / 155 mph`.

However, it's important to note that we don't have information about when the cars start. If we assume they start at the same time, we can calculate the value of "t" using the above formula. But if they start at different times, we need additional information to accurately determine the catch-up time.