College

The table below shows the data for a car stopping on a wet road. What is the approximate stopping distance for a car traveling 35 mph?

Car Stopping Distances:

[tex]\[
\begin{tabular}{|c|c|}
\hline
v \text{ (mph)} & d \text{ (ft)} \\
\hline
15 & 31.8 \\
\hline
20 & 41.7 \\
\hline
50 & 97.4 \\
\hline
\end{tabular}
\][/tex]

Using the formula:

[tex]\[ q(v) = \frac{2.15 v^2}{64.4 f} \][/tex]

Options:
A. 41.7 ft
B. 49.7 ft
C. 97.4 ft
D. 115.3 ft

Answer :

To find the approximate stopping distance for a car traveling at 35 mph on a wet road, we use the formula provided:

[tex]\[ q(v) = \frac{2.15 \times v^2}{64.4 \times f} \][/tex]

where:
- [tex]\( v \)[/tex] is the speed of the car in miles per hour (mph),
- [tex]\( f \)[/tex] is the friction factor, which is typically assumed around 0.7 on wet roads.

Let's go through the steps to calculate this:

1. Identify the given speed: The car's speed, [tex]\( v \)[/tex], is 35 mph.

2. Use the typical friction factor for wet roads: Without a specific value given, we'll use [tex]\( f = 0.7 \)[/tex].

3. Plug these values into the formula:

[tex]\[ q(35) = \frac{2.15 \times (35)^2}{64.4 \times 0.7} \][/tex]

4. Perform the calculation:
- First, calculate [tex]\( 35^2 \)[/tex], which is 1225.
- Multiply 1225 by 2.15, getting 2637.75.
- Multiply 64.4 by 0.7, which is 45.08.
- Finally, divide 2637.75 by 45.08 to get approximately 58.42 ft.

The approximate stopping distance for a car traveling at 35 mph on a wet road is about 58.4 feet.