A copy of the self-help book “Atomic Habits” has sold approximately every 15 seconds since its 2018 release. To date, over 10 million copies of James Clear’s blockbuster have been rung up. Those staggering results are a testament to our desire to improve and the challenge of doing so successfully.

Atomic Habits teaches readers how to form good habits, break undesirable habits, and master small actions that lead to significant results. I’ve written about how Atomic Habits can be applied to finance, so I won’t revisit that here. 

I recently heard Clear discussing the leverage of content. He described work that continues to pay off long after the job is done. First, Clear compared a radio interview to recording a podcast. After a radio interview has aired, it’s done, gone from the airwaves. Those who weren’t listening won’t hear it. But podcasts are recorded — they live on. A podcast episode recorded years ago can continue accumulating new audience members and potential customers. 

Then, he provided another example about a blog post he had written that didn’t go viral or generate many views initially. Years later, a major newspaper writer read the post and wanted to interview Clear for an upcoming story. A TV producer read that story and invited him to appear on a major television show. He leveraged that appearance into a follow-up appearance to announce his book Atomic Habits. The clip from that show was sent to his email list to publicize the book launch. These cascading developments could be traced back to a seemingly insignificant blog post written several years earlier. 

That blog post was The Physics of Productivity: Newton’s Laws of Getting Stuff Done. After reading the post, I felt compelled to write this one as an homage to Clear’s original post and to narrow the concept’s scope to personal finance.

Not to worry, you don’t need to understand physics to apply Newton’s rules of motion to other areas of your life, including personal finance. But a bit of background, if nothing else, but for the intrigue might be worthwhile. 

Sir Issac Newton was an English physicist and mathematician. If you struggled with Calculus in school —blame Newton. But he also formulated the theory of universal gravity, which transformed scientific thinking and set in motion (pun intended) an era of discovery and advancement in explaining the physical world.

Newton’s “The Principia — Mathematical Principles of Natural Philosophy,” published in 1687, was a monumental work. In The Principia, he mathematically explored principles of time, force, and motion.

We’ll focus our attention on Newton’s three laws of motion. 

Newton’s First Law of Personal Finance 

First Law of Motion: An object either remains at rest or continues to move at a constant velocity unless acted upon by an external force. (i.e., Objects in motion tend to stay in motion. Objects at rest tend to stay at rest.)

The most dangerous word in personal finance is — “later.” Atomic Habits author James Clear goes further, declaring:

 “In many ways, procrastination is a fundamental law of the universe.” 

Fortunately for all of us, whether it comes to productivity or personal finance, once we get the ball rolling, we tend to keep moving. Whether your financial goals involve paying down debt, saving for retirement, or building generational wealth, the most important thing is to find a way to generate the initial motion. 

Starting doesn’t have to be difficult. It could be as simple as automating monthly contributions to a retirement account or cutting a few subscription services to reduce monthly expenses. The key is not remaining at rest.

Newton’s Second Law of Personal Finance

Second Law of Motion: F=ma. The vector sum of the forces on an object is equal to the mass of that object multiplied by the acceleration vector of the object. (i.e., Force equals mass times acceleration.)

The formula goes: force is equal to mass times acceleration. In Newton’s second law, both acceleration and force are vector quantities. Let’s suppose we have a concrete block floating in space. If you were to apply a net force (F) on one side of that block, you’d have a net acceleration going in the same direction. Or, as Clear described it,”:

"If you want to get an object accelerating in a particular direction, then the size of the force you apply and the direction of that force will both make a difference."

This Newtonian principle can be applied to personal finance as well as physics. Let’s say you have an extra $500 a month to invest. That’s important, but your results will vary based on where you apply that force. If you speculate on risky penny stocks, you’re likely to have very different results than if you were to buy a basket of high-quality stocks.

Each of us has a limited amount of economic force. We can increase that force by increasing our income or cutting our expenses, but we must also consider where we apply that force. If we push in the wrong direction, our results will not match our expectations. Thanks, Sir Issac. 

Newton’s Third Law of Personal Finance

Third Law of Motion: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body. (i.e., Equal and opposite forces.)

“You probably know that the Earth pulls down on you. What you might not realize is that you are also pulling up on the Earth. For example, if the Earth is pulling down on you with a gravitational force of 500 N, you are also pulling up on the Earth with a gravitational force of 500 N. This remarkable fact is a consequence of Newton’s third law. (Khan Academy).”

There are positive uses of financial means (savings, education, experiences, health) and negative ones (short-lived desires, unused subscriptions, impulse buying). Your overall financial picture is typically a balance of these positive and negative forces. 

To continue following Clear’s framework - we have two options to move closer to our financial goals. The first is through brute force, like working longer hours or taking a second job. This can be effective, especially in the short term. But when taken too far or being done for too long leads to burnout as we relentlessly try to overwhelm our hostile forces. 

Another option Clear presented is to eliminate opposing forces. We all waste money on things that don’t provide value to our lives. We all make purchases on a whim that we quickly regret. We all fall victim to our short-sighted desires. By eliminating (or reducing) these negative forces, positive momentum will result. Not only is this method more sustainable for the long term, but it’s also far less stressful. 

Newton’s Laws of Personal Finance Summarized

Newton’s laws of motion reveal ways we can progress toward our financial goals. 

1. Objects in motion tend to stay in motion. Don’t stay at rest — start small and start now. 

2. It’s not just about force; it’s also about how and where you apply that force. 

3. Your financial results are a balance of opposing forces. If you want to move forward, you can either brute force your way through barriers or remove the opposing forces. The second option is usually less stressful and more sustainable.