[urgent] simple mechanical energy question [gr.11] Several children, pretending they are playing in the jungle, suspend a rope from an overhead tree limb. A child of mass 40 kg running at 8.0m/s grabs the rope and swings off the level ground. a) What maximum height does the child reach? b) How fast would a 30 kg child have to run to reach the same height as the 40 kg child? ½mv1²+mgh1 = ½mv2²+mgh2 a) m=40kg, v1=8.0m/s, h1=0m, g=9.8m/s², v2=0m/s (at max height v=0) h2=? ½mv1²+mgh1 = ½mv2²+mgh2 ½mv1²= mgh2 h2 = 3.27m = 3m (is this correct?) im really confused with B... coz i got 8m/s... it doesn't make sense to me how they can run at the same speed and achieve the same height??!! this is really urgent... so please help me!! >_< thanks!