JEE Main 29 June 2022 Shift 2 Solved Paper

A block of mass 40‌kg slides over a surface, when a mass of 4‌kg 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. (Given g=10ms−2.)