In order to calculate the new speed of the cart, we can use the formula for conservation of momentum:
[tex]m_1v_1=m_2v_2[/tex]Using m1 = 1200, v1 = 10.8 and m2 = 1696 (that is, 1200 plus 496), we have:
[tex]\begin{gathered} 1200\cdot10.8=1696\cdot v_2 \\ v_2=\frac{1200\cdot10.8}{1696} \\ v_2=7.64 \end{gathered}[/tex]So the new speed of the loaded cart is 7.64 m/s.