Acceleration of a car followed by abrupt stop

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To calculate the acceleration of a vehicle that decelerates from 90 km/h to a complete stop in 13 seconds, the correct formula to use is a = (Vi - Vf) / T. The initial velocity (Vi) is 90 km/h, and the final velocity (Vf) is 0 km/h. However, it's crucial to ensure that the units are consistent; either convert time to hours or velocity to km/s. If the velocity remains in km/h, the acceleration will be in km/h², while converting to km/s will yield acceleration in km/s². Proper unit conversion is essential for obtaining the correct answer.
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Homework Statement


What is the acceleration of a vehicle that changes its velocity from 90 km/h to a dead stop in 13 s?



Homework Equations



i don't understand how to do this correctly

The Attempt at a Solution



i know I am supposed to use the formula for acceleration [a= (Vi-Vf)/T] i plugged in 90 for the Vi and 0( the dead stop) for Vf after that i divided by 13 but the answer i got was wrong.
 
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Double check your units.
 
you mean convert to meters?
 
No. Your velocity is given in km/h and your time is given in s; they need to coordinate before you can just plug them in. You need to either convert your time to hours (in which case acceleration units would be km/h2) or convert your velocity to km/s (acceleration would be in km/s2).
 

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