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.

 

[m2003]

Thank you for providing your response. I would agree with your calculation of the time it takes for the speed of the object to reach zero. The only potential issue I see is with the initial velocity given as +4 m/s, which could indicate a positive acceleration rather than the given negative acceleration of -15 m/s2. However, assuming that the given values are correct, your calculation and answer appear to be correct. It is possible that the discrepancy in the answer is due to significant figures, as you mentioned. It is important to pay attention to these details in scientific calculations to ensure accurate results.