일반물리학 1 — Force and Motion-II: Problem 55

55 A bolt is threaded onto one end of a thin horizontal rod, and the rod is then rotated horizontally about its other end. An engineer monitors the motion by flashing a strobe lamp onto the rod and bolt, adjusting the strobe rate until the bolt appears to be in the same eight places during each full rotation of the rod (Fig. 6-44). The strobe rate is 2000 flashes per second; the bolt has mass 33 g and is at radius 4.0 cm. What is the magnitude of the force on the bolt from the rod?