I'm trying to do an experiment about earthquake... I used a pendulum and an "angle meter" (is that what it's called?) to measure the maximum angular displacement of the ball, thus define the strength of the earthquake. I measured the height the ball goes (enable me to find potential energy), and reason the bigger the angle, the stronger the earthquake (common sense, I know, but my teacher wants some calculation). But now my teacher want me to use tangential and radial acceleration to calculate the earthquake force...I try to read, but it seems strange somehow...I can't think of a way to calculate this... Could someone help me, please? Thanks in advance!!