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anonymous
 4 years ago
A student drives by a stationary police car at 41.7m/s, exactly 7s later the policeman starts after the speeding car, accelerating at a steady 3.75m/s2. How long after the police car begins moving does it take to catch up with the speeding car.
i got 34.8s but its wrong, can anyone explain it.
Xcar= 291.9+41.7t
Xpolice= 1.875t2
Xcar=X police 1.875t241.7t291.2
t=34.8s
anonymous
 4 years ago
A student drives by a stationary police car at 41.7m/s, exactly 7s later the policeman starts after the speeding car, accelerating at a steady 3.75m/s2. How long after the police car begins moving does it take to catch up with the speeding car. i got 34.8s but its wrong, can anyone explain it. Xcar= 291.9+41.7t Xpolice= 1.875t2 Xcar=X police 1.875t241.7t291.2 t=34.8s

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anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0equation i used was Xf= Xi +Vit+ (1/2)at^2

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Is 291.9 the distance the car travels in seven seconds?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Looks good. Double check that you used the correct solution to the quadratic.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Maybe its just a typo in the solution manual......it has 23.8s

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0The math gods seem to agree. http://www.wolframalpha.com/input/?i=0.5*3.75*%28t7%29%5E2+%3D+41.7*t

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0@mathmate did you use the same equation?

mathmate
 4 years ago
Best ResponseYou've already chosen the best response.2I used your equation (corrected) and got 27.833, which is the same answer as eashmore's answer by subtracting 7 seconds.

mathmate
 4 years ago
Best ResponseYou've already chosen the best response.2Can you double check the data (speed, acceleration, 7 seconds, etc.)

mathmate
 4 years ago
Best ResponseYou've already chosen the best response.2Note that the clock starts when the police car moves, which is t=7 in eashmore's equation.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yea data is correct.......since the police car moves 7 seconds later i have cars position as t+7

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Here is a better representation : http://www.wolframalpha.com/input/?i=0.5*3.75*%28t%29%5E2+%3D+41.7*%28t%2B7%29

mathmate
 4 years ago
Best ResponseYou've already chosen the best response.2Guess the answer key has a typo!
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