Posted by **mely** on Thursday, January 20, 2011 at 12:43am.

The "reaction time" of the average automobile driver is about 0.700 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 12.0 ft/s^{2}, compute the total distance covered in coming to a stop after a signal is observed (a) from an initial velocity of 15.0 mi/h (in a school zone) and (b) from an initial velocity of 55.0 mi/h.

- physics -
**drwls**, Thursday, January 20, 2011 at 8:13am
The total stopping distance is:

X = Vo*(reaction time) + (a/2)*(deceleration time)^2

Reaction time = tr = 0.70 s

Deceleration time = Vo/a

X = Vo*tr + (1/2)(Vo^2)/a

(a) If Vo = 15 mi/h = 22 ft/s,

X = 22*(0.700) + (1/2)(22/15)^2/0.12

= 15.4 + 6.1 = 21.5 ft

(b) repeat calculation for Vo = 55 mi/h = 80.67 ft/s

## Answer This Question

## Related Questions

- physics - a typical automobile has a maximum deceleration of about 7m/s2, the ...
- Physics - Traveling at a speed of 15.9 m/s, the driver of an automobile suddenly...
- Physics - Traveling at a speed of 16.1 m/s, the driver of an automobile suddenly...
- physics - A car is traveling at a constant velocity of 21 m/s (about 45 mph). ...
- Physics - A car is going 18.3 m/s down a road. At time t=0s, a squirrel runs in ...
- Physics - You are driving down the highway late one night at 20 m/s when a deer ...
- physics - n automobile traveling at a speed of 29.3 m/s applies its brakes and ...
- physics - A car is moving at 90 km/h when the driver notices an animal that is ...
- Physics - The brakes of an automobile are suddenly applied at the instant when ...
- physics - How do i go about this question? Suppose a car is traveling at 20.0m/s...

More Related Questions