If freshwater resources are to be used sustainably, which of the following do you
think will have the greatest impact:
building more water treatment plants,
using less water, or cleaning wastewater
before returning it to the ecosystem?

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?