Hi guys, I've got a doubt concerning to the minimum mechanical work and the work-energy theorem. Consider the following Tippens' problem (8.4): A 5-kg hammer is lifted to a height of 3 m. What is the minimum required work? The answer looks very simple and inocent, W = weight times distance. However, deeping inside we can calculate the negative work done by the gravity, it would be: W = -weight times distance. So, the total work is equal to zero and if we assume that the hammer starts from rest then its final velocity have to be equal to zero too (work-energy theorem). It's very confusing for me how this could be possible, how a displacement could be obtained if at any time the velocity is equal to zero. Also is confusing how being the total force equal to zero (weight - weight = 0) the motion is possible. Thanks in advance for your help.