What are the similarities between business risk and financial risk?

1. [WACC]
What are the similarities between business risk and financial risk? Everything else equal, would you advice a higher debt ratio for a company that has high business risk? Why?
or
[CAPM model ]
Why is the biggest advantage of having debt in a company? According to the trade-off theory, as managers choose how much debt to raise for their company, what are the competing risks that they need to consider?
2. [ using balance sheet and income statement to calculate FCF ]
As you calculate FCF, there are three main components, cash flow from operations which comes from the income statement and change in net operating working capital (NOWC) and change in net fixed assets (NFA) from balance sheet statements. Why are we calculating changes for the components that are obtained from balance sheet but the actual number for the component that comes from the income statement? Why do we subtract the change in NOWC and NFA from the cash flow from operations to get FCF for the year?
Or
[What increases FCF in a given year? ]
List different ways a manager can increase its company’s free cash flow in a given year. Is increasing current year FCF always a good idea? Why or why not?