Consider a block and trolley system as shown in figure. If the coefficient of kinetic friction between the…

Consider a block and trolley system as shown in figure. If the coefficient of kinetic friction between the trolley and the surface is $0.04$, the acceleration of the system in $\mathrm{m} {\mathrm{s}}^{-2}$ is: (Consider that the string is massless and unstretchable and the pulley is also massless and frictionless) :