The “reaction time” of the average automobile driver is about 0.7 s. (The reaction time is the interval between the perception of a signal to stop and the application of the brakes.) If an automobile can slow down with an acceleration of 12 ft/s^2 compute the total distance(in feet) covered in coming to a stop after a signal is observed from an initial velocity of 55 mi/h. Let 1 mi/h= 1.466 ft/s.

Question

The “reaction time” of the average automobile driver is about 0.7 s. (The reaction time is the interval between the perception of a signal to stop and the application of the brakes.) If an automobile can slow down with an acceleration of 12 ft/s^2 compute the total distance(in feet) covered in coming to a stop after a signal is observed from an initial velocity of 55 mi/h. Let 1 mi/h= 1.466 ft/s.
271 ft
327 ft
113 ft
414 f

I have absolutely no idea. If you could please show me what to do and how to get the answer and check my answer. That would be amazing! Thanks!

bobpursley · Accepted Answer

distance before slowing: 55 *1.466ft/sec*.7sec=56.1ft check that. distance while braking: vf^2=vo^2+2ad d= (55*1.466)^2/(2*12)=271ft add the two distances

Babygirl · Answer

Thanks so much! You’re the GOAT!

Babygirl · Answer

Wait so is 271 the answer?

bobpursley · Answer

check it. Taking my answer is ridiculous. I am trying to show you how to work it.

bobpursley · Answer

and the answer is, no it is not the answer. Add the distances.

Babygirl · Answer

What distances? 12 and what else?

Babygirl · Answer

12 and 55? If so, is the answer 338 which is not an answer choice.

bobpursley · Answer

56.1ft +271= ???

tommy · Answer

so whats the answer?