Question

An accident investigator measured the skid marks of the car. The length of the skid marks was $76$ feet. Use the formula $s=\sqrt{24d}$ to find the speed of the car before the brakes were applied. Round your answer to the nearest tenth.

Short answer

The speed of car is$42.70$mph

Step-by-step solution

Given information

Given the speed of car is given by$s=\sqrt{24d}$

Substitute d=76 and calculate the speed

Substituting, we get

$$\begin{gathered} d=\sqrt{24\times 76} \\ d=\sqrt{1824} \\ d=42.70 \end{gathered}$$

Checking the speed

Checking, we get

$$\begin{gathered} 42.70=\sqrt{24\times 76} \\ 42.70=\sqrt{1824} \\ 42.70=42.70 \end{gathered}$$

So its true