일반물리학 1 — Potential Energy and Conservation of Energy: Problem 23

23 The string in Fig. 8-26 is \(L = 120 \text{ cm}\) long, has a ball attached to one end, and is fixed at its other end. The distance \(d\) from the fixed end to a fixed peg at point \(P\) is \(75.0 \text{ cm}\). When the initially stationary ball is released with the string horizontal as shown, it will swing along the dashed arc. What is its speed when it reaches (a) its lowest point and (b) its highest point after the string catches on the peg?