1. The problem statement, all variables and given/known data The pendulum shown (http://puu.sh/chwMZ/90f4b96fb1.png [Broken]) swings freely, turning around at a height of 10 cm above the lowest point in its swing. It has an unknown mass, but air resistance can be ignored. a) Use energy conservation to find its speed at the lowest point of its swing. b)What is the pendulum speed when it is at a height of only 1 cm above its lowest point? 2. Relevant equations PE=mgh V^2 = (2PE)/m 3. The attempt at a solution I know I need to use the two equations above. But I don't know how. I can't understand how to do this problem. Therefore there is no attempted solution. I am not asking for a solution, I want to learn, but can someone explain to me what to do here?