In mechanical terms, a flywheel is a wheel so heavy it takes significant effort to start turning. Keep applying force, though, and it builds momentum -- and in time becomes more stable while helping itself turn faster and faster.

In Good to Great, Jim Collins applied the premise to business, showing how a company's flywheel is a self-reinforcing loop made up of a few key initiatives that both feed and drive each other.

One obvious example: Amazon. Here's how Brad Stone describes an early version of Amazon's flywheel in The Everything Store:

...Bezos and his lieutenants sketched their own virtuous cycle, which they believed powered their business. It went something like this: Lower prices led to more customer visits. More customers increased the volume of sales and attracted more commission-paying third-party sellers to the site. That allowed Amazon to get more out of fixed costs like the fulfillment centers and the servers needed to run the website. This greater efficiency then enabled it to lower prices further.

Feed any part of this flywheel, they reasoned, and it should accelerate the loop.

A less obvious example? Dwayne Johnson.

Early on, Johnson didn't have a flywheel. But as The Rock, what he did have was a talent for professional wrestling: in-ring, on mic, behind the scenes. Every aspect. He leveraged those skills, and the resulting popularity, to earn TV roles and his eventual breakout role in The Mummy Returns. 

But what you might not know is that he and 7 Bucks Productions co-founder Dany Garcia leveraged wrestling and acting to build a production company that creates original releases for film, TV, and digital platforms. Acting fueled the production company, which in turn fueled his acting career. (Why not develop or co-develop some of the projects you're in?) 

All of which, in turn, helped fuel outside business interests. Like an athletic wear collaboration with Under Armour. Like ZOA, the top-selling new energy drink of 2021

And most notably Teremana Tequila, a spirits brand launched last March that sold over 600,000 cases, making it the biggest 12-month new-to-market brand debut ever.

That success can be partly tied to relationships with leading importer Mast-Jagermeister U.S. and Southern Glazer's Wine & Spirits distributors. That success can also be tied to the brand's taste and accessible price point. (If you like, think of Teremana as "The People's Tequila.")

But that success is also a result of Johnson's now-advanced flywheel. He's the top-grossing actor in the world. (The recently released Red Notice gathered a record-breaking 330 million views on Netflix and hit the service's top 10 rankings in 94 countries.) On social media, his more than 290 million followers make him the most-followed American in the world. 

Acting fuels social media and business, which in turn fuel acting: Not just in terms of box office and followers and revenues, but also in terms of relationships and partnerships.

More naturally begets more: Additional force to any one input on his flywheel creates more of every input on his flywheel. Case in point: Mast-Jagermeister just announced it will become an investor in Teremana, a move designed to further foster the brand's global expansion and distribution.

All of which, if you do the math and apply a few assumptions, likely means Johnson's flywheel has made him a billionaire. George Clooney sold his Casamigos brand for a deal worth $1 billion ($700,000 up front and an additional $300 million if certain sales targets are hit). At that time, Casamigos had sold 120,000 cases the previous year.

Compare that to Teremana's 600,000-plus cases sales in its first year and, even though the price points -- and possibly margins -- are different, the potential is arguably much greater. Lower cost typically leads to broader appeal, which should make it easier for Teremana to leverage its extensive distribution network to expand into other lines and territories.

And of course there's Johnson himself, whose constantly growing on-screen and social-media popularity -- along with his prodigious ability to authentically connect with millions of people -- helps drive brand awareness and brand affinity.

Granted, those are all assumptions. But they're pretty good ones. So yeah: Dwayne Johnson, master of the flywheel -- and as a result, likely billionaire.

I know what you're thinking. "Interesting. But how does that apply to me?"

Here's how. If you only have one primary initiative or area of focus -- whether in business or in your personal life -- what happens when the momentum from that initiative inevitably stalls?

The key is to build a flywheel that, when you feed any part of it, naturally accelerates the entire loop.

Don't feel bad if your flywheel is currently missing a facet or two. Once upon a time, Johnson's was. Just make sure you start working to create your own self-reinforcing wheel.

Because when you do can make your business or personal life really roll.