How do you calculate deceleration due to resistance?

[cpalm]

I have a rocket with a top velocity of 14.16 m/s when the engine stops.

How do i calculate its deceleration based on air resistance and gravity if it is flying at approximatly 45 degress?

 

[Delphi51]

There is no easy way to deal with air resistance. It is ignored in most courses.
Also, we usually simplify matters by saying the engine burns for so small a time it is effectively zero.

So, it is just another baseball problem. Do the horizontal and vertical parts separately.