Question

The stopping distance d of an automobile is directly proportional to the square of its speed s.

On one road, a car requires 75 feet to stop from a speed of 30 miles per hour. How many feet
does the car require to stop from a speed of 48 miles per hour on the same road?

Answer 1

192 feet is the stopping distance at 48 mph.

Explanation:

Set up the proportion
`(x)/(75) =(48^(2) )/(30^(2) )`

x/75 = 2304/900 cross multiply to get 900x = 172800

172800 ÷ 900 = 192

x = 192