Question

The equation s=21d−−−√ relates a car's speed, s, in miles per hour (mph) to the length of a skid in feet.

A car goes into a skid at 72 mph. We can expect a skid of


feet. Round your answer to the nearest whole foot.

Answer 1

To find the length of the skid in feet when a car is skidding at 72 mph, we can use the equation:

s = 21d^(1/2)

Given:

s = 72 mph

Let's substitute the value of s into the equation and solve for d:

72 = 21d^(1/2)

To isolate d, we need to eliminate the square root. We can do this by squaring both sides of the equation:

72^2 = (21d^(1/2))^2

5184 = 21d

Now, solve for d by dividing both sides of the equation by 21:

d = 5184 / 21

d ≈ 247.43

Therefore, the skid length is approximately 247.43 feet. Rounded to the nearest whole foot, the expected skid length would be 247 feet.

Explanation: