ده موقع بيحسب مسافه التوقف
www.csgnetwork.com/stopdistcalc.html
ودي لعبه بتبين سرعه رد الفعل و الفرمله وعلاقتهم بالمسافه
http://www.4shared.com/file/72124333...oadSafety.html
Stopping Distance Calculation
For calculating minimum stopping distance, a value of 0.8 is a nominal value for the coefficient of static friction between good tires and a good road surface. Almost always, coefficients of kinetic friction are less, and are dramatically less for wet, icy, slick, sandy, dirty very smooth or oily surfaces. For many newer high performance tires with good tread, the coefficient of kinetic friction on a dry road surface may approach 0.8 if the braking is not so prolonged as to cause tire melting. You may wish to plug in a smaller value such as .7 or .6 for a vehicle with normally driven and worn tires. Poor condition tires might yield .5 or .4 for a closer representation of friction.
لو اعتبرنا ان معامل التماسك (الاحتكاك ) هو الحاله المثاليه ... يعني U=0.8
عند سرعه 180كم ساعه ..... حتكون مسافه التوقف 159.5 متر
ولو فيه اي عوامل مؤثره على معامل الاحتكاك ( الاسفلت ... الحراره .... ضغط العجل .... )
عند U=0.7 ..... حنلاقي مسافه التوقف تبقى 182 متر
Stopping Distance For A Vehicle
Assuming proper operation of the brakes on the vehicle, the minimum stopping distance for a vehicle is determined by the effective coefficient of friction between the tires and the road, and the driver's reaction time in a braking situation. The friction force of the road must do enough work on the car to reduce its kinetic energy to zero. If the wheels of the car continue to turn while braking, then static friction is operating, while if the wheels are locked and sliding over the road surface, the braking force is a kinetic friction force only.
To reduce the kinetic energy to zero:
so the stopping distance is