Which Equation Should Be Used for Finding Maximum Constant Deceleration?

[sandman203]

Homework Statement

Hi all this is just a quickie, but in one of my texts a question asks to find the maximum constant deceleration given an initial speed, time to stop and the distance it took.

Now I am not sure whether to use v = u + at or s = 1/2at^2 + ut

im thinking more v = u + at because I am not given displacement, I am given a distance.. any thoughts? cheers!

 

[CWatters]

Do both give the same answer?

 

[rcgldr]

If it's constant acceleration, and the given inputs are the initial speed and time to stop, there there is only one possible constant acceleration (deceleration). The maximum and minimum would be the same. I'm not sure why that was mentioned. It the distance to stop is also given, it either corresponds to the time, or else there's a conflict in the problem statement.

 

[SteamKing]

Why would you think, in this case, that displacement is not equal to distance?