These 2 Physics Videos Can Help You Understand Newton's 3rd Law of Motion

Credit: Derbeth/Flickr

By Andrew Bennett

You’ve likely heard of Sir Isaac Newton’s 3rd Law of Motion, "For every action, there is an equal and opposite reaction." But what does it really mean?

What Is Newton's 3rd Law of Motion?

Many people (even teachers) wrongly think that Newton’s 3rd Law is somehow linked to cause and effect and that the effect is somehow the opposite of the cause. This is simply wrong.

What the law really means is that forces come in pairs. In other words, when two objects interact with each other, each object applies a force to the other. The forces the objects apply are equal in size and opposite in direction.

3rd Law Videos

Newton's 3rd Law of Motion Definition and Examples

In the first video, you will learn about the general principle of Newton’s 3rd Law. You will also learn a helpful naming system for forces that will help you identify 3rd Law pairs. Finally, you will see several examples of how 3rd Law pairs work.

Newton's 3rd Law of Motion Demo

Another misconception people have about the 3rd Law is: "If Newton's 3rd predicts an equal and opposite force to whatever force I apply, then the object I'm applying a force to could never move because the forces balance."

The second video shows why that thinking is incorrect with data collected from two carts connected by a string. In the demonstration, you will see that each cart experiences the same force in the string. However, the lead cart experiences a larger force in the string pulling it forward than in the string that connects it to the other cart.

Subscribe for More Physics Videos

Did you like these videos? Make sure you subscribe to my channel to see more videos about physics laws, demos, equations, experiments, and more!

Comments

Why Do They Do That? The Physics Behind 3 Famous Animal Behaviors

By Amber Bennett Have you ever wondered about the origins of the phrase, "get your ducks in a row"? What about how the "doggy paddle" works or why squirrels are such amazing jumpers? The answers to all of these questions have one thing in common: physics. Keep reading to learn about the science behind these three famous animal behaviors. How Do Squirrels Leap from Branch to Branch? A squirrel leaps through the air. Photo Credit: caroline legg , CC BY 2.0 , via Wikimedia Commons The death-defying acrobatic maneuvers performed by squirrels look a lot like parkour tricks. But how do they know how to land tricky jumps between bendy tree branches that move with the wind? Researchers say it's a combination of learned behavior (practice makes perfect) and inherited adaptations. To see what determines how far a squirrel is willing to jump and how the leaps are timed, researchers set up an obstacle course in an artificial forest. Then, they used peanuts ...

3 Easy Science Experiments to Do with Your Kids

By Amber Bennett Strong STEM (science, technology, engineering, and math) skills set kids up to succeed both in school and later in life. Encouraging them to be interested in these subjects is easier than you might think, especially if you start when they're young. Activities that encourage children to be curious and creative will spark a love of learning. Plus, science experiments and other hands-on STEM projects are a fun way to bond with your kids. Here are three easy science experiments that preschoolers and early elementary students will enjoy. 1. Leakproof Plastic Bag A (age 5) doing the leakproof plastic bag experiment. Our preschooler loves to do any experiment that involves water. I can give her a couple of beakers, and she'll happily pour water back and forth between them, especially if I put a few drops of food coloring in each beaker so she can mix the colors. Another great activity that involves water is the leakproof plastic bag. All you need are: Large p...

How Virtual Currency Mining Is Hurting the Environment - Science in the News

Datacenters used for cryptocurrency mining use a lot of energy. By Amber Bennett Although cryptocurrencies are virtual, they are having a tangible impact on our environment. Research shows that cryptocurrencies actually are worse for the earth than other types of money. So, why is that? Simply put, it's because of the resources needed to run the supercomputers that mine Bitcoin and other virtual currencies. Energy Use The datacenters used for mining use large amounts of electricity. For example, the global Bitcoin network uses more energy than entire countries . In fact, according to the University of Cambridge Bitcoin Electricity Consumption Index , the network's power demand is the same as more than 14 million typical American homes. Most of the energy used in the datacenters comes from fossil fuels instead of renewable resources. Plus, datacenters' high energy use can destabilize the electric grid. Materials Mining Another way that cryptocurrency impacts the environme...

Bennett Science Blog

Search This Blog