What is the logic behind the NPV capital-budgeting framework?

What is the logic behind the NPV capital-budgeting framework? Would changes in the cost of capital ever cause a change in the IRR ranking of several projects? When it is clear that a project will be profitable, why should it be rejected if it has a negative net present value? Why should cash flow to be received at the end of six years be discounted more heavily than cash flow to be received at the end of five years?

find the cost of your paper