Very basic acceleration question (typo?)

[mujadeo]

An object starts at time t = 0 with a velocity of v = +4 m/s and undergoes a constant acceleration of a = -15 m/s2
At what time does the speed of the object reach zero?

so,
vf = vi + a t
so delta t = 0 - 4 / -15

= .27 seconds

apparentrly this is wrong answer, but I can't see why? seems really simple!

I am suspecting that this question had a typo in it?

Sorry, please disregard, it was sig dig problem
should be .267 seconds!

 

[Cyrus]

Thanks for posting this in the Homework Help section mujadeo.