Meriam, Kraige & Bolton — Plane Kinetics of Rigid Bodies: Problem 6_98

6/98 The figure shows an impact tester used in studying material response to shock loads. The 60-lb pendulum is released from rest and swings downward with negligible resistance. At the bottommost point of the motion, the pendulum strikes a notched material specimen A. After impact with the specimen, the pendulum swings upward to a height h' = 3.17 ft. If the impact-energy capacity of the pendulum is 300 ft-lb, determine the change in the angular velocity of the pendulum during the interval from just before to just after impact with the specimen. The center-of-mass distance \(\bar{r}\) from O and the radius of gyration \(k_O\) of the pendulum about O are both 35.5 in. (Note: Positioning the center of mass directly at the radius of gyration eliminates shock loads on the bearing at O and extends the life of the tester significantly.)