1. The problem statement, all variables and given/known data To protect his food from hungry bears, a boy scout rasies his food pack with a rope that is thrown over a tree limb at height h above his hands. He walks away from the vertical rope with constant velocity (v boy), holding the free end of the rope in his hands. (a) Show that the speed v of the food pack is given by (x)(x^2 + h^2)^(-1/2)(v boy) where x is the distance he has walked away from the vertical rope The diagram given is something like this, |\ | \ | \ | \ | \ |___\ -------------> * The diagram is not coming out properly, anyhow its a right angled triangle. with the below characteristics. *h is the constant distance between the tree top and the hand of the boy (the vertical line) *x is the variable horizontal distance (the horizontal line) *The point where the diagonal and vertical line meet is like the "pivot". That is where the rope goes one round around a twig. * ----> is v boy 2. Relevant equations 3. The attempt at a solution V = distance displaced / time Distance displaced = (h^2 + x^2)^(1/2) - h Assumption ? < The change in diagonal length when the boy moves = distance displaced > According to Pythagoras theorem the above (h^2 + x^2)^(1/2) is derived. And the change being the ( final diagonal distance - initial diagonal distance (when x=0) ). So I have come until this point, but I am unable to simplify it further so that its similar to the equation I'm supposed to derive. Can anyone hint to me or guide me along on which part I have made a mistake or whats the possible next step? Thanks P.s: hope the drawing helps. If any additional information is needed do tell me so that i can take a look and see whether its provided. A BIG THANKS again.