The question is in the attachment. a) for the height i got 1.25m which you get by using displacement and acceleration. (t=20/40=0.5sec) b) a=v/t, 10*0.5=5m/s c) At initial point: mgh= 0.040*10*1.25=0.5J 1/2mv^2=1/2*0.040*40^2=32J Hits Ground: mgh=0.040*10*0=0J 1/2mv^2=1/2*0.040*(20 or 40)^2 ?????? The answer is 32.5J im not sure what happens here and how to get that. Do you add the energys from initial point together???