Question

A boy of mass M swings back-and-forth to the end of room for 6 m long there’s attached to the ceiling of a gymnasium. If he approaches to within 2 m of the ceiling during each cycle, what is the speed as he passes through the lowest point of the swing

Answer 1

$$0.5mv^2=mgh\\v^2=2gh\\v^2=2(9.8)(6-2)\\v=8.85\frac{m}{s}$$