Two blocks of masses 3kg and 5kg are connected by a spring of stiffness k. The coefficient of friction between the blocks and surface is 0.2 . Find the minimum constant horizontal force F to be applied to 3kg block in order to just slide the 5kg block.
My work : For 5kg block to just slide, the spring force should be equal to friction experienced by it which is equal to 10N. Now the external force F applied on 3kg block should be greater than or equal to the spring force + friction due to surface which is equal to 10N + 6N = 16N . So my result is that the minimum force should be equal to F = 16N. But this is not the answer. I want to know where am I wrong. Ans - F =11 N