S equals square root of 30 times D times f times n end root

Where:

S = speed in miles per hour
30 = a constant value used in the equation
D = length of the skid marks in feet
f = drag factor for the road surface
n = braking efficiency as a percent

If a car’s speed is 70 miles per hour on a road surface with a drag factor of 0.50 and with a breaking efficiency of 85% (n = .85), what would be the length of the skid marks? Round to the nearest tenth.

S=sqrt(30*D*f*n)

s^2=30*D*f*n
d=70^2/(30*.5*.85) about 385 feet. check that

Well, let's put on our clown shoes and solve this equation step by step. We have S = √30 * D * f * n.

Since we're looking for the length of the skid marks, which is represented by D, let's isolate it.

First, square both sides of the equation to get rid of the square root: S^2 = (30 * D * f * n).

Now, divide both sides of the equation by (30 * f * n): S^2 / (30 * f * n) = D.

Plugging in the given values: S^2 / (30 * 0.50 * 0.85) = D.

So, (70^2) / (30 * 0.50 * 0.85) = D.

Calculating that, we get D ≈ 136.3 feet.

Therefore, the length of the skid marks, rounded to the nearest tenth, would be approximately 136.3 feet. Drive safely and try not to leave too many skid marks!

To find the length of the skid marks (D), we can substitute the given values into the equation:

S = √(30 * D * f * n)

Given:
S = 70 (speed in miles per hour)
f = 0.50 (drag factor)
n = 0.85 (braking efficiency as a decimal)

Substituting these values, the equation becomes:

70 = √(30 * D * 0.50 * 0.85)

Now let's solve for D.

To find the length of the skid marks, we can use the formula:

S = √(30 * D * f * n)

Given:
S = 70 miles per hour
f = 0.50
n = 85% = 0.85

We need to convert the speed from miles per hour to feet per second because the length of the skid marks is given in feet.

To convert miles per hour to feet per second, we need to multiply by a conversion factor: 1 mile = 5280 feet and 1 hour = 3600 seconds.

Step 1: Convert the speed from miles per hour to feet per second:
70 miles per hour * (5280 feet / 1 mile) * (1 hour / 3600 seconds) = 102.67 feet per second (rounded to two decimal places)

Now we can substitute the values into the formula:

102.67 = √(30 * D * 0.50 * 0.85)

To solve for D, we need to isolate it.

Step 2: Square both sides of the equation to eliminate the square root:

102.67^2 = (30 * D * 0.50 * 0.85)

10,536.0389 = 6.375D

Step 3: Divide both sides of the equation by 6.375:

10,536.0389 / 6.375 = D

1,651.1333 = D

The length of the skid marks, rounded to the nearest tenth, would be 1651.1 feet.