Khan/khan-exercises — Issue #4334: Kinematic equations - Account for + and - in quadratic formula
Author: KhanBugz
Created: 2011-10-13 22:23:32+00:00
State: open
Labels: ie8, win7

Reporter: tim1miner@frontier.com

Kinematic equations problem:
d = -1318.3m
Vf = -199.04 m/s
a = -14.8m/s^2
find t...
2 valid answers are 11.8s and 15.1s
depending on direction of initial velocity...
1) you only accept one answer
2) you provide no criteria to select one over the other
3) I admit to staying a bit confused

[kinematic_equations.html?seed=170&problem=0](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/kinematic_equations.html?seed=170&problem=0)

[["15.1","s"]]

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