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**

| Speed (mph) | Distance (ft) |
|-------------|---------------|
| 15 | 17.9 |
| 20 | 41.7 |
| 50 | 97.4 |

Use the formula [tex]\(a(v) = \frac{2.15 v^2}{64.4}\)[/tex].

Possible stopping distances:
A. 41.7 ft
B. 49.7 ft
C. 97.4 ft

Answer :

Sure! Let's determine the approximate stopping distance for a car traveling at 35 mph on a wet road using the provided formula:

1. Identify the values needed: To calculate the stopping distance, we need the speed of the car, which is 35 mph, and the coefficient of friction, which is typically estimated for a wet road. In this case, we assumed an estimated coefficient of friction of 0.7.

2. Use the formula: The stopping distance can be calculated using the formula:
[tex]\[
a(v) = \frac{2.15 \times v^2}{64.4 \times f}
\][/tex]
where [tex]\( v \)[/tex] is the speed in mph, and [tex]\( f \)[/tex] is the coefficient of friction.

3. Plug in the values:
[tex]\[
a(35) = \frac{2.15 \times 35^2}{64.4 \times 0.7}
\][/tex]

4. Calculate the intermediate values:
- First, calculate [tex]\( 35^2 \)[/tex], which is the square of the speed: [tex]\( 35^2 = 1225 \)[/tex].
- Next, multiply this by 2.15: [tex]\( 2.15 \times 1225 = 2638.75 \)[/tex].

5. Calculate the denominator:
- Multiply 64.4 by the coefficient of friction 0.7: [tex]\( 64.4 \times 0.7 = 45.08 \)[/tex].

6. Divide the results:
- Complete the division: [tex]\( \frac{2638.75}{45.08} \approx 58.42 \)[/tex].

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