Newton's Third Law of Motion

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Questions and Answers

What is the name given to Newton's third law of motion?

The Action-Reaction Law (correct)

Law of Universal Gravitation

The Law of Inertia

The Law of Momentum

What happens when one object exerts a force on another object?

The second object exerts a force in the same direction

The second object exerts a force in the opposite direction (correct)

The second object exerts no force at all

The second object moves at a constant velocity

What is the reason why action forces and reaction forces do not cancel each other out?

Because the forces are not opposite

Because the forces are not simultaneous

Because the forces are not equal

Because the forces act on different objects (correct)

What is the result of the person exerting a force on the water in the rowboat example?

The water moves backward Signup and view all the answers

What is the relationship between the action force and the reaction force in Newton's third law?

The action force is equal to the reaction force Signup and view all the answers

What would happen if the equal and opposite forces were exerted on the same object?

The forces would cancel each other out Signup and view all the answers

What is the main idea behind Newton's third law of motion?

That every action has an equal and opposite reaction Signup and view all the answers

What happens when the action and reaction forces occur on the same object?

The motion is cancelled Signup and view all the answers

Why can't a person in a rowboat propel the boat forward on land?

Because the cup of water would exert a small amount of force on the person and the rowboat Signup and view all the answers

What is the reaction force exerted on a rocket ship due to its engine?

An upward force Signup and view all the answers

How do fighter jets operate?

By using an action force on the air behind them Signup and view all the answers

What is the purpose of a water mill according to Newton's third law of motion?

To generate electricity Signup and view all the answers

What is the result of the action force exerted by a person's muscles on the ground while walking?

The ground exerts a reaction force pushing the person forward Signup and view all the answers

What happens when a person in a rowboat exerts a force on the water?

The water exerts a reaction force on the rowboat, propelling it forward Signup and view all the answers

What is necessary for a rocket ship to propel upward?

The reaction force of the expanding gases on the rocket must be greater than the mass of the rocket Signup and view all the answers

Study Notes

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction.
When one object exerts a force on a second object, the second object exerts a force on the first that is equal but opposite in direction.

Examples of Action and Reaction Forces

Rowboat: person exerts force on water using a paddle, and the water exerts a reaction force on the person and the rowboat.
Rocket ships: engine propels an action force on expanding gases, and the expanding gases exert an equal reaction force on the rocket, propelling it upward.
Fighter jets: engine exerts an action force on air behind it, and the air exerts a reaction force on the fighter jet, propelling it forward.
Cars: engine and tires exert an action force on the ground, and the ground exerts a reaction force on the car, pushing it forward.
Bicycles and walking: muscles create an action force on the ground, and the ground exerts a reaction force on the person, allowing them to move forward.

Key Points

Action forces and reaction forces are equal but opposite in direction.
Forces do not cancel each other out because they act on different objects.
The cancellation of motion occurs only when both action and reaction forces are exerted on the same object.

Applications of Newton's Third Law of Motion

Conversion of motion into electricity, e.g., using a water mill to generate electricity.
Rocket propulsion: the action force of the engine is equal to the reaction force of the expanding gases, propelling the rocket upward.

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Description

Explore Newton's third law of motion, also known as the action-reaction law, which states that every action has an equal and opposite reaction. Learn how it applies to forces and interactions between objects. Test your understanding with this quiz!