The Charpy impact test is one test that measures the resistance of a material to fracture....

The Charpy impact test is one test that measures the resistance of a material to fracture. In this test, the fracture toughness is assessed by measuring the energy required to break a specimen of a given geometry. This is done by releasing a heavy pendulum from rest at an angle θi, and then measuring the maximum swing angle θf reached by the pendulum after the specimen is broken.

Figure P8.29

Consider a test rig in which the striker S (the pendulum’s bob) can be modeled as a uniform disk of weight WS = 40 lb and radius rS = 6 in., and the arm can be modeled as a thin rod of weight WA = 5.5 lb and length LA = 2.75 ft. If the release angle of the striker is θi = 158° and if the striker impacts the specimen when the pendulum’s arm is vertical, determine the speed of the point Q on the striker immediately before the striker impacts with the specimen. Neglect friction and observe that the striker and the arm are rigidly connected.