1. The problem statement, all variables and given/known data Tarzan is swinging on the end of a vine, the vine is 6m long and is attached to the top of a tree. Tarzan weighs 90kg. At the highest level, he is 2.25 meters above ground and the lowest level 0 meters above ground. Questions: At which point is the centripetal force/acceleration at its greatest and how big is it? 2. Relevant equations F = ma a = v^2 / r 3. The attempt at a solution I draw an angle and show his weight (mg), and have drawn relevant lines aswell. See the picture. Okay, mg is the force downwards. mg is a cathetus, and you can extend the centripetal force so that it is another cathetus and mg is the hypothenuse. Alright. I have marked two angles which are the same. So how do we calculate "centri"? We need to know an angle and one side/hypothenuse. We know one cathetus. So let's call the angle x. Tan x = mg / centri. Tan x * centri = mg. How do I continue from here? How do I know at which point it is the biggest and how big it is?