In this activity, students will apply their knowledge of kinematics to a tailgating problem. After testing individual reaction times and researching deceleration rates of various automobiles, they will use a computer model to test the safe following distance for a given situation. They will compare the results from the model to the safe following rule given to them in the driver's education classes.

TEACHER RESOURCES Teacher Materials Student Activity Student    Assessment Learning    Goals/Standards COMPUTER MODEL PC Format Mac Format STELLATM software Web-based Simulation AUTHORS Charlotte Trout   Williamsport HS   Williamsport, MD Based on Nicklin, R. C. "The Kinematics of Tailgating" The Physics Teacher Vol 35, Feb 1997, p.78-79

THE MODEL DIAGRAM THE EQUATIONS Distance_Back_Car(t) = Distance_Back_Car(t - dt) + (Chg_Dist_Back) * dt INIT Distance_Back_Car = 0 Chg_Dist_Back = Velocity_Back_Car*1.47 Distance_Front_Car(t) = Distance_Front_Car(t - dt) + (Chg_Dist_Front) * dt INIT Distance_Front_Car = Carlengths_Between*16 Chg_Dist_Front = Velocity_Front_Car*1.47 Velocity_Back_Car(t) = Velocity_Back_Car(t - dt) + (- Decel_Back_Car) * dt INIT Velocity_Back_Car = Initial_Velocity_Back Decel_Back_Car = if time<(5+Rxn_Time_Back) then 0 else Decel_Rate_Back*0.682 Velocity_Front_Car(t) = Velocity_Front_Car(t - dt) + (- Decel_Front_Car) * dt INIT Velocity_Front_Car = Initial_Velocity_Front_mph Decel_Front_Car = IF time<5 then 0 else Decel_rate_Front*.682 Carlengths_Between = 4 Collision = if Collision_Velocity>0 then PAUSE else 0 Collision_Velocity = if (Distance_Front_Car-Distance_Back_Car)>0 then 0 else Relative_Velocity Decel_Rate_Back = 28 Decel_rate_Front = 28 Distance_Between = ABS(Distance_Front_Car-Distance_Back_Car)/16 Initial_Velocity_Back = 45 Initial_Velocity_Front_mph = 45 Relative_Velocity = DELAY(ABS(Velocity_Front_Car-Velocity_Back_Car),DT) Rxn_Time_Back = 0.45

THE OUTPUT

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