- Why do we tend to get Newton’s Laws wrong in our heads?
- Why do physics problems always involve “frictionless slopes” and “massless ropes”?
Imagine an object. Think of something with a bit of weight to it, like a small wooden treasure chest or a fresh loaf of good, dense olive bread. Or, once again, you can go ahead and try this simple experiment in real life.
Now imagine that you start to push this object. You keep pushing until it’s got a good speed going, and then you let go. What happens next?
You have watched this exact scenario play out an uncounted number of times in your life, and so you probably have a pretty good idea of the results. The object will move forward for a little while, and then eventually it will slow down and stop.
After observing this behaviour over and over again, most people develop an unconscious version of Newton’s First Law in their own heads. Their version goes something like this: Everything, no matter how fast it’s going, will eventually slow down and stop. And, surprise surprise, this is wrong.