1. The problem statement, all variables and given/known data The speed of a particle of mass m varies with space as v(x) =ax^-n v(x=0)=0 at t=0. Find F(x). 2. Relevant equations F=ma=m dv/dt 3. The attempt at a solution I am not really sure where to start from. Would x(t) or f(t) be relevant?