Assuming a frictionless pulley and slope, the vertical component of the weight on the slope is 5gsin30=5g/2 newtons. The net vertical force on the weight hanging from the pulley is (8-5/2)g newtons = 5.5g N. Newton's law says F=ma, where F is the force, m the mass on which the force is acting and a the acceleration. a=5.5g/8. the acceleration due to gravity, g, is 9.81 m/s^2, so the acceleration is 5.5*9.81/8=6.74m/s^2.