Questions: The formula s = 2√fL can be used to approximate the speed s, in miles per hour, of a car that has left skid marks of length L, in feet. How far will a car skid at 60 mph? The car will skid feet.

Solution Steps

The formula given is \( s = 2\sqrt{fL} \), where:

• \( s \) is the speed in miles per hour,
• \( L \) is the length of the skid marks in feet,
• \( f \) is the coefficient of friction (not given in the problem).

To find the skid distance \( L \), we need to rearrange the formula to solve for \( L \). Start by isolating \( \sqrt{fL} \):

\[ \sqrt{fL} = \frac{s}{2} \]

Square both sides to eliminate the square root:

\[ fL = \left(\frac{s}{2}\right)^2 \]

Solve for \( L \):

\[ L = \frac{s^2}{4f} \]

We are given that the speed \( s = 60 \) mph. Substitute this value into the equation:

\[ L = \frac{60^2}{4f} = \frac{3600}{4f} = \frac{900}{f} \]

Final Answer