Why are inputs and outputs important to the world?

Which is not true about oxygen-17 and oxygen-18?

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?

Which describes increasing the efficiency of energy resource