All the technology we rely on, from cars to smartphones, was designed with physics in mind. You don’t need to know science to use these things. But a well-rounded person must understand at least some of the key concepts—along with music, art, history, and economics. Robert Heinlein said it all Time enough for love,

“A man must be able to change a diaper, plan an invasion, make a hog a pig, design a ship, design a building, write a sonnet, balance accounts build, build a wall, set a leg, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch, program a computer, cook a nice meal, fight efficiently, die gallantly. Specialization is for insects. “

So, in the interest of you not being insects, here are my top five physics equations you should know.

1. Newton’s second law

I’m sure you’ve seen it before—it’s over 300 years old, and it’s popular for science memes and t-shirts. The net force on an object is said to be equal to its mass (m) times acceleration (a). But what does that really mean? It’s all about interactions – like when you kick a soccer ball or drop a water bottle on the floor.

Newton’s second law says we can describe these interactions with the concept of ‘force’. And what do forces do? The net force on an object changes the motion of the object. But wait! There are a lot more fun things in this simple equation.

Notice those arrows F and a? This indicates variables that are vectors, meaning they contain more than one piece of information. For example, if someone asked you to “socially distance” yourself by 1 meter, where would you end up? Who knows? You can go 1 meter to the east or west or 39 degrees from North. The distance in itself is not the full story; You must also specify a direction. This applies to both the forces and the acceleration. Other quantities (such as mass or temperature) do not have direction. We call those scalar values.

Newton’s second law is very useful, but strangely, people don’t seem to believe it. The common misconception is that a constant force causes an object to move at a constant velocity. Rather, what this equation says is that if you push an object with a constant force, it will continue to accelerate.