Question

According to the formula for stopping distance, how many feet will it take you to stop, from 60 mph?

Answer 1

Answer:

534 ft

Explanation:

given,

speed of the vehicle = 60 mph

1 mph = 0.447 m/s

60 mph = 60 x 0.447 = 26.82 m/s

stopping distance = ?

Stopping distance of the car is equal to the distance traveled in the reaction time and the braking distance.

Reaction time of a common person = 1.5 s

taking coefficient of friction of the road = 0.3

using equation of stopping sight distance

S.D = RD + BD

RD is Reaction distance

RD = v t_r

RD = 26.82 x 1.5

RD = 40.23 m

BD is the braking distance

$BD = \dfrac{v^2}{2\mu g}$

$BD = \dfrac{26.82^2}{2\times 0.3\times 9.8}$

BD = 122.33 m

Stopping sight distance

SD = 40.23 + 122.33

SD = 162.56 m

1 m = 3.28 ft

162.56 m = 162.56 x 3.28

                = 533.20 ft ≈ 534 ft

hence, the stopping distance will be equal to 534 ft