f a car is speeding down a road at 40 miles/hour (mph), how long is the stopping distance D40 compared to the stopping distance

Question

3 months ago

6

f a car is speeding down a road at 40 miles/hour (mph), how long is the stopping distance D40 compared to the stopping distance

D25 if the driver were going at the posted speed limit of 25 mph? Express your answer as a multiple of the stopping distance at 25 mph. Note that D25 is already written for you, so just enter the number. View Available Hint(s)

Physics

1 answer:

kicyunya [3.2K] · Answer 1 · 2026-03-02T07:47:34+03:00

Answer:

D40 = 2.56 × D25

This means the stopping distance at 40 mph is 2.56 times that at 25 mph

Explanation:

provided data

speed = 40 miles/hour

distance = D40

speed limit = 25 miles/hour

distance = D25

to determine

express how the stopping distance relates to the 25 mph distance

solution

it is established that stopping distance varies directly with the square of the speed

thus speed ratio is

initial speed = $\frac{40}{25}$

thereby, initial speed = 1.6

so

stopping distance increase = (1.6)²

$\frac{D40}{D25}$ = (1.6)²

$\frac{D40}{D25}$ = 2.56

therefore

D40 = 2.56 × D25

This shows that the stopping distance at 40 mph is 2.56 times that at 25 mph