Well one night I thought it was a great idea to go to the gym and lift some weights. Well i was wrong, becasue the next day, i could not lift my arms, and if i tired i almost cried in pain. Well, i started to think about it and there was a lot of work done while i was lifting those weights. I picked up my 3.6 kg dumbells and started to lift them above my head .46m. I did 3 sets of 12 and that was enough for me. But, i can calculate the amount of work done for one rep. Well, W=Fd and the force= ma there for F=(3.6kg)(9.81m/s2) = 35N and when plugged into W=Fd= (35N)(.46m)= 16.1J. May not seem like a lot, but it sure did feel like it! maybe next time I'll pass o nthe gym and do some serious work sitting on my couch and watching tv!!