1. The problem statement, all variables and given/known data If we know that velocity [itex]v[/itex] of a particle as a funciton of position [itex]x[/itex] is: $$v(x)=20-2/3x$$ then i am asked to determine the acceleration when [itex]x=15[/itex]. I am then asked to show that the particle never actually reaches [itex]x=30[/itex] 2. Relevant equations $$vdv=adx$$ $$vdt=dx$$ $$adt=dv$$ and [itex]a[/itex] is the acceleration (not necessarily constant) and [itex]t[/itex] is time. 3. The attempt at a solution I have already reduced the problem to what we see in [itex]1.[/itex] I have tried to work with the relevant equations but i cant make sense of the second two since they are time-dependent, which is a variable i have no information on. However, intuitively, i feel to answer the second part i would take a limit as t approaches infinity, so I am conflicted. Thanks everyone for the help! you people are awesome!!