일반물리학 1 — Potential Energy and Conservation of Energy: Problem 35

35 In Fig. 8-30, a block of mass $m = 3.20\text{ kg}$ slides from rest a distance $d$ down a frictionless incline at angle $\theta = 30.0^\circ$ where it runs into a spring of spring constant $431\text{ N/m}$. When the block momentarily stops, it has compressed the spring by $21.0\text{ cm}$. What are (a) distance $d$ and (b) the distance between the point of the first block-spring contact and the point where the block's speed is greatest?