A boy is sitting on a swing at a maximum height of 5m above the ground. When the swing passes through the mean position which is 2m above the ground his velocity is approximately
7.6 m/s
By the conservation of energy Total energy at point A = Total energy at point B
⇒mgh1=mgh2+12mv2
⇒9.8×5=9.8×2+12v2
⇒v2=58.8 ∴v=7.7m/s(appx.)