Asked by lance
A 745i BMW car can brake to a stop in a distance of 122 ft from a speed of 60.0 mi/h. To brake to a stop from a speed of 80.0 mi/h requires a stopping distance of 221 ft. What is the average braking acceleration for the following intervals? Express the answers in mi/h/s and in m/s^2
60 mi/h to rest, 80 mi/h to rest,80 mi/h to 60 mi/h
60 mi/h to rest, 80 mi/h to rest,80 mi/h to 60 mi/h
Answers
Answered by
GK
Vf^2 = Vo^2 + 2ad
0 = Vo^2 + 2ad
Vo^2 = -2ad
At 60 mph:
V^2 = -2ad => a = -V^2/2d
a = (60.0 mi/h)^2 / (2)(0.0231mi)
a = -77901.64 mi/h^2
1 mi/h^2 = 3600 mi/(h*s) (why?)
1 mi/(h*s) = 1609m/(3600s)(1s) = 0.447 m/s^2
a = -21.64 mi/h/s = -9.67 m/s^2
You calculate the acceleration when Vo = 80 mph in a similar fashion.
0 = Vo^2 + 2ad
Vo^2 = -2ad
At 60 mph:
V^2 = -2ad => a = -V^2/2d
a = (60.0 mi/h)^2 / (2)(0.0231mi)
a = -77901.64 mi/h^2
1 mi/h^2 = 3600 mi/(h*s) (why?)
1 mi/(h*s) = 1609m/(3600s)(1s) = 0.447 m/s^2
a = -21.64 mi/h/s = -9.67 m/s^2
You calculate the acceleration when Vo = 80 mph in a similar fashion.
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.