A marble block of mass $m_{1}=559.1 \mathrm{~kg}$ and a granite block of mass $m_{2}=128.4 \mathrm{~kg}$ are connected to each other by a rope that runs over a pulley as shown in the figure with Problem $4.89 .$ Both blocks are located on inclined planes with angles $\alpha=38.3^{\circ}$ and $\beta=57.2^{\circ} .$ The rope glides over the pulley without friction, but the coefficient of friction between block 1 and the inclined plane is $\mu_{1}=0.130,$ and that between block 2 and the inclined plane is $\mu_{2}=0.310 .$ (For simplicity, assume that the coefficients of static and kinetic friction are the same in each case.) What i the acceleration of the marble block? Note that the positive $x$ -direction is indicated in the figure.