A block of mass \( 40 \; \text{kg} \) slides over a surface, when a mass of \( 4 \; \text{kg} \) is suspended through an inextensible massless string passing over frictionless pulley as shown below:
The coefficient of kinetic friction between the surface and block is \( 0.02 \). The acceleration of block is. \( \text{(Given } g = 10 \; \text{ms}^{-2}\text{)} \).
