(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The "reaction time" of the average automobile driver is about 0.700 . (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 12.0 , compute the total distance covered in coming to a stop after a signal is observed (a) from an initial velocity of 15.0 (in a school zone) and (b) from an initial velocity of 55.0 .

x=?

xo=?

vx=0, point at which you are stopped

vxo=15 mi/h initial speed

ax=-12 ft/s^2

t=?

2. Relevant equations

v=d/t

vx^2=vxo^2+2ax(x-xo)

3. The attempt at a solution

I am pretty much lost, I tried converting everything to meters as that is what the answers call for, and got the equation

vx^2-vxo/2ax= (0)^2 -(6.7056)^2/ 2(-3.6576)= 6.1468 meters

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Driver reaction time, with negative acceleration

**Physics Forums | Science Articles, Homework Help, Discussion**