1. The problem statement, all variables and given/known data Joe ascends a small hill from an elevation of 250m to an elevation of 490m. In doing so he expends 2.8x10^5J. If Joe's mass is 75kg what is the efficiency of his climb? 2. Relevant equations W= change in E= change in Ek + change in Ep Ep= mgh Ek= 0.5mv^2 %efficiency=useful energy output/total energy input x 100% 3. The attempt at a solution should i use the work energy theorem to solve the problem?