Current Attempt in Progress

A cart is propelled over an $xy$ plane with acceleration components $a_x=5\mathrm{.}0\frac{m}{s^2}$ and $a_y=-2\mathrm{.}1\frac{m}{s^2}.$ Its initial velocity has components $v_{0x}=8\mathrm{.}4\frac{m}{s}$ and $v_{0y}=11\mathrm{.}8\frac{m}{s}.$ In unit$-$vector notation, what is the velocity of the cart when it reaches its greatest y coordinate?