Would you like to measure your reation time? Would you like to estimate how fast you can drive on the highway?

Try this. Just Press  (each clicks to the start button will create a new window)

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Your browser can't run 1.0 Java applets, so here's a picture ofthe window the program brings up:

 

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What you need to do: Click the Brake button when the red light turns on. (Not just pressed on it)

• The time delay between the red light is turned on and you click the brake button will be shown in the textfield.
  (plus the time needed to stop the car after the brake is started. The corresponds distances which the car moved are also shown on the graph)
• Paramenters you can change
  • Initial Velocity of the car : initial value is 72 km/h = 20 m/s
    You can select the unit for the velocity ( km/h, mile/h or m/s)
  • Friction coefficient of tires on the road : initial value is 0.8
• The Y-coordinate the the small dots are proportional to the velocity of the car
  Notice that it is not a straight line after the brake turned on! Because ...
• The mouseXV textfield shows X-coordinate and velocity of the car at the mouse position.
  If you drag the mouse, it will change to values of the relative distance and the relative velocity.
  (relative to the point where you started to drag the mouse)
• Press Reset button to restart the testing.
• Close the window to Quit.

Reaction time : the lapse of time between stimulation and the beginning of response.

You are driving on the high way and listening to the music you like most.

Suddently, you see the brake light of the car in front of you just turned on.

You will try to hit the brake and slow down your car.

But, there is a small time delay before you really do that--- your reaction time.

During that period of time, your car is still moving at the same HIGH speed!

If you do not want something VERY BAD happened,

What is minimum diatance between front of your car and the rear of the car before yours?

If both cars need the same distance to fully stopped, the miniuum distance is

( the velocity of your car )* ( your reaction time )

*** <need to be finished>