A body of mass 5kg starts from the origin with an initial velocity  $\overrightarrow{\mathrm{u}}=30\widehat{\mathrm{i}}+40\widehat{\mathrm{j}}{\mathrm{ms}}^{-1}$. If a constant force  $\overrightarrow{\mathrm{F}}=-(\widehat{\mathrm{i}}+5\widehat{\mathrm{j}})\mathrm{N}$ acts on the body, the time in which the y- component of the velocity becomes zero is