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 at 35 mph?

Car Stopping Distances

[tex]
\[
\begin{tabular}{|c|c|}
\hline
\multicolumn{2}{|c|}{$v$ (mph)} \\
\hline
\end{tabular}
\]
[/tex]

[tex]
\[ a(v) = \frac{2.15 v^2}{64.4 f} \]
[/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 have a formula provided:

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

In this formula:
- [tex]\( v \)[/tex] represents the speed of the car in mph.
- [tex]\( f \)[/tex] is the friction coefficient, which on a typical wet road can be assumed to be around 0.7.

Let's break down the steps to find the stopping distance:

1. Identify the given values:
- The speed [tex]\( v \)[/tex] of the car is 35 mph.
- The friction coefficient [tex]\( f \)[/tex] is 0.7.

2. Substitute the given values into the formula:
- Replace [tex]\( v \)[/tex] with 35 mph.
- Replace [tex]\( f \)[/tex] with 0.7.

The formula becomes:

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

3. Calculate [tex]\( 35^2 \)[/tex]:
- [tex]\( 35^2 = 1225 \)[/tex].

4. Plug in the value and simplify the equation:

[tex]\[ a(35) = \frac{2.15 \times 1225}{64.4 \times 0.7} \][/tex]

[tex]\[ a(35) = \frac{2637.75}{45.08} \][/tex]

5. Divide the values:
- [tex]\( a(35) \approx 58.42 \)[/tex].

Therefore, the approximate stopping distance for a car traveling 35 mph on a wet road is 58.42 feet.