A block of mass m = 4 kg is kept on an incline connected to a spring (see fig). The angle of the incline is `theta = 30^(@)` and the spring constant is K = 80 N/m. There is a very small friction between the block and the incline. The block is released with spring in natural length. Find the work done by the friction on the block till the block finally comes to rest.[`g = 10 m//s^2`]
