The potential energy `U`(in `J`) of a particle is given by `(ax + by)`, where `a` and `b` are constants. The mass of the particle is `1 kg` and `x` and `y` are the coordinates of the particle in metre. The particle is at rest at `(4a, 2b)` at time `t = 0`.
Find the coordinates of the particle at `t =1` second.
A. `(3.5a,1.5b)`
B. `(3a,2b)`
C. `(3a,3b)`
D. `(3a,4b)`