Mrs. Fine had a car accident. According to the police investigation, her car make skid marks which were 42 ft in length. What was the speed of the car of Mrs. Fine at the time of the accident? Did she manage to follow the speed limit?

To determine the speed of the car, we need more information. The length of the skid marks alone is not sufficient to calculate the speed accurately. However, we can provide some general information and steps to calculate the possible speed of the car:

1. Determine the average deceleration rate:
- The deceleration depends on various factors such as tire grip, road conditions, and braking system.
- A common estimate used by accident investigators is around 10-30 feet per second squared (ft/s^2) for typical road surfaces.

2. Calculate the time it took for the car to come to a stop:
- We need to know the time it took for the car to stop completely, which is not mentioned in the given information.
- If the time is provided, we can use the kinematic equation: vf = vi + at, where vf is the final velocity (0 ft/s), vi is the initial velocity (speed of the car), a is the deceleration rate, and t is the time.

3. Calculate the speed of the car:
- Once you have the time, use the equation vf = vi + at to calculate the speed of the car (initial velocity) before the accident.
- If the time is not provided, it is not possible to determine the speed accurately based solely on the length of skid marks.

In conclusion, without the time it took for the car to come to a stop or additional information, it is not possible to determine the speed of the car accurately. It is essential to consider multiple factors and evidence in accident investigations.

To determine the speed of Mrs. Fine's car at the time of the accident, we need to use the formula of skid distance and speed.

The formula to calculate skid distance is:

Skid Distance = (Speed^2) / (2 * Deceleration)

Here, Deceleration refers to the rate at which the car slows down during braking. For most vehicles, it is assumed to be a constant value of 32.2 ft/s^2.

Given that the skid distance is 42 ft, and deceleration is 32.2 ft/s^2, we can rearrange the formula to solve for speed:

Speed = sqrt(2 * Deceleration * Skid Distance)

By plugging in the known values, we can calculate the speed:

Speed = sqrt(2 * 32.2 ft/s^2 * 42 ft)

Calculating this gives us:

Speed = sqrt(2703.6 ft^2/s^2)

Speed ≈ 52 ft/s

To convert the speed from ft/s (feet per second) to mph (miles per hour), we can multiply by the conversion factor 0.681818:

Speed ≈ 52 ft/s * 0.681818 (ft/s to mph conversion factor)

Speed ≈ 35.5 mph

Therefore, the speed of Mrs. Fine's car at the time of the accident was approximately 35.5 mph. To determine whether she was exceeding the speed limit, we would need to know the specific speed limit for the location of the accident.