What is Newton's Third Law of Motion | Action and Reaction Forces with Examples | Dr. Binocs Show

Summary

This educational video explores Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. It uses relatable examples like sitting on a chair and a bird flapping its wings to explain how forces interact. The video also touches on how mass and acceleration affect these forces, using the example of a gun's recoil when firing a bullet. It concludes with a historical note on Newton's publication of the laws of motion and a trivia question, making the content both informative and engaging.

Takeaways

• 🔍 Newton's third law of motion states that for every action, there is an equal and opposite reaction.
• 🧐 The law helps us understand how forces interact in the physical world, such as when you push against something, it pushes back with equal force.
• 💺 Examples include sitting on a chair, where the action force is your body's weight and the reaction force is the chair's support.
• 🐦 Forces can be contact forces like friction or non-contact forces like gravity, as illustrated by a bird flapping its wings.
• 🎯 Action and reaction forces are equal in magnitude but opposite in direction, balancing each other out.
• 🚀 The recoil of a gun when firing a bullet is an example of Newton's third law, where the bullet and gun exert equal and opposite forces.
• 🤔 The effect of forces on an object depends on its mass and acceleration, as explained by Newton's second law.
• 🚢 The mass of an object affects how it reacts to forces; a heavy ship will move less than a small boat when pushed with the same force.
• 📚 Newton's laws of motion were first published in 1687 in his book 'Mathematical Principles of Natural Philosophy'.
• 🎨 The sketch of the day was provided by Amaya Rajput, highlighting the educational content of the video.

Q & A

What is Newton's third law of motion?

Newton's third law of motion states that for every action, there is an equal and opposite reaction. This means that whenever a force is applied to an object, the object applies a force back that is equal in magnitude but opposite in direction.

How does the action-reaction force pair relate to the concept of forces in physics?

In physics, forces are pushes or pulls that occur during the interaction of objects. The action-reaction force pair is a direct manifestation of this concept, where the action force is the initial force applied, and the reaction force is the equal and opposite force exerted by the second object.

Why do we need to understand Newton's first and second laws before diving into the third law?

Understanding Newton's first and second laws provides a foundational context for the third law. The first law (inertia) and the second law (force equals mass times acceleration) help explain how objects resist changes in motion and how acceleration is affected by force and mass, which are key to understanding the interaction of action and reaction forces.

Can you give an example of action and reaction forces in everyday life?

Yes, when you sit on a chair, your body exerts a downward force (action) due to gravity, and the chair exerts an equal and opposite upward force (reaction) to support you, preventing you from falling through it.

What are the two main types of forces mentioned in the script?

The two main types of forces mentioned are contact forces, such as friction, and non-contact forces, such as gravity.

How does the mass of an object affect its reaction to forces?

The reaction of an object to forces depends on its mass and the amount of acceleration it experiences. According to Newton's second law, heavier objects will accelerate less for the same force applied compared to lighter objects.

Why doesn't the gun fly back as fast as the bullet when fired?

The gun doesn't fly back as fast as the bullet because it has a much greater mass. According to Newton's second law, the acceleration of an object is directly proportional to the net force acting upon it and inversely proportional to its mass. Thus, the gun's larger mass results in a smaller acceleration and less recoil.

What happens when you jump out of a boat onto the shore?

When you jump out of a boat onto the shore, you push the boat backward (action), and the boat pushes you forward (reaction), helping you reach the shore. The boat, being less massive compared to you, moves away due to the applied force.

Why does pushing a huge ship have a minimal effect compared to pushing a small boat?

Pushing a huge ship has a minimal effect because the ship's mass is significantly larger than your own, and the force you apply has a negligible impact on its movement. This results in almost no movement of the ship, while you still experience the reaction force that propels you forward.

Who first stated the three laws of motion and in what year were they published?

The three laws of motion were first stated by Sir Isaac Newton in his book 'Mathematical Principles of Natural Philosophy,' which was originally published in 1687.

What is the significance of today's sketch of the day mentioned in the script?

Today's sketch of the day is significant as it represents a visual summary or interpretation of the discussed concept, in this case, Newton's third law of motion, and is credited to Amaya Rajput.