The potential energy of a particle of mass $\mathrm{5 }\mathrm{k}\mathrm{g}$ moving in the $\mathrm{x}-\mathrm{y}$ plane is given by $\mathrm{U}=\left(-7\mathrm{x}+24\mathrm{y}\right)\mathrm{ }\mathrm{J}$, where $\mathrm{x}$ and $\mathrm{y}$ are in meters. If $\mathrm{t}=0$, the particle starts from rest from the origin, then speed of the particle at $\mathrm{t}=\mathrm{2 }\mathrm{s}$ is