The rear end is often occur on the highway traffic accident, the important reason is unable to stop immediately encountered an unexpected condition. The study found, the driver from see to slam on the brakes need a period of time, this paragraph of time is called the reaction time to the car in the reaction timeMaintain the original speedForward a distance, this distance is called reaction distance; from stepping on the brake to stop, the car will move a distance, this distance is called the braking distance. As shown in Fig.17As shown in.

 The table below is an alert the driver driving a car is well maintained cars, in the level of highway drying at different speed

When driving, reaction distance and braking distance measured.

(1Using the table data), reaction time, the driver is about           S(retained two decimal places)

(2By the test of visible),               Is the main factor affecting the automobile braking distance;

 3. Please in Fig.18Draw the driver to see the situation from the beginning of time, this time the car to stop, the car movementV-TImage. (without accurate tracing point)

1 0.66~0.68 　 ⑵ Speed      It is shown in Figure 18, the image does not to the abscissa or on the abscissa below, all button1Divided