A force ${\text{F}}_{\text{1}}$ acting on a 2 kg body produces an acceleration of $2.5{\text{ms}}^{-2}$ . Another force  ${\text{F}}_{\text{2}}$  acting on a 5 kg body produces an acceleration of $2{\text{ms}}^{-2}$ . The forces  ${\text{F}}_{\text{1}}$ and  ${\text{F}}_{\text{2}}$ are