A lonely child is swinging on a rusty old swing set, as seen in the image provided. If friction does 145 J of work slowing the swing, what is the maximum speed she can reach?

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.