High School

Determine the stopping distance for a car traveling at 35 mph using the following information:

**Car Stopping Distances:**

[tex]
\[
\begin{tabular}{|c|c|}
\hline
$v$ & $d$ \\
$(\text{mph})$ & $(\text{ft})$ \\
\hline
15 & 17.9 \\
\hline
20 & 31.8 \\
\hline
50 & 198.7 \\
\hline
\end{tabular}
\]
[/tex]

The stopping distance formula is:
[tex] a(v) = \frac{2.15 v^2}{64.4 f} [/tex]

**Options for the stopping distance at 35 mph:**

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

Answer :

To find the stopping distance of a car traveling at 35 mph, we can use the formula provided for calculating stopping distance:

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

where:
- [tex]\( v \)[/tex] is the velocity in miles per hour (mph),
- [tex]\( a(v) \)[/tex] is the stopping distance in feet.

Let's plug in the values and calculate the stopping distance step-by-step:

1. Identify the velocity: We are given that the car is traveling at [tex]\( v = 35 \)[/tex] mph.

2. Use the formula:

Substitute [tex]\( v = 35 \)[/tex] into the formula:
[tex]\[ a(35) = \frac{2.15 \cdot 35^2}{64.4} \][/tex]

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

[tex]\( 35^2 = 1225 \)[/tex].

4. Insert this into the formula:

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

5. Calculate the numerator:

[tex]\( 2.15 \times 1225 = 2637.5 \)[/tex].

6. Divide by 64.4 to get the stopping distance:

[tex]\[ a(35) = \frac{2637.5}{64.4} \][/tex]

7. Perform the division:

[tex]\[ a(35) \approx 40.90 \][/tex]

So, the stopping distance for a car traveling at 35 mph is approximately 40.9 feet.