A wall is tilted in by $15^{\large\circ}$,and a 2kg block is placed against the wall.The block is held in place with a spring.The coefficients of friction between the block and the wall are $\mu_s=0.61$ and $\mu_k=0.49$.Holding the block in place requires that the spring be compressed by 12cm.What is the spring constant of the spring?
