Physics 1205
Assignment #11



Problem A: You are ice skating on a (frictionless) lake with a friend when an unfortunate accident occurs triggered by a strange series of events. First, your friend who is skating very fast, about 20 m/s loses his balance and begins sliding on the ice at that same speed. He crashes into a log that is lying flat on the ice. The log is 3.0 meters long and has twice his mass. He impacts the log exactly at one end of the log at an angle perpendicular to the length of the log and he holds onto the log. The crash causes the log to move along the ice and to rotate around the center of mass of your friend and the log (now stuck together). The end of the log swings around and the end of the log that your friend is not stuck to hits you in the leg giving you a very nasty bruise. The collision between the log and your leg occurred just at the point where the log had rotated 180 degrees from its original position and the sum of the translational velocity and rotational velocity was the greatest. How fast was the end of the log moving when it hit your leg?