Do Now If you are sitting still in your seat on a bus that is traveling 100 km/h on a highway, is your body at rest or in motion? Explain your answer. Use a diagram if it will help make your answer clear. Record your response in your science journal.

Learning Target Today I will: Learn newton’s three laws So that I can: solve problems involving each of the laws. I will know I got it if: I can solve word problems related to Newton’s three laws.

Objectives Describe Newton’s first law of motion, and explain how it relates to objects at rest and objects in motion. State Newton’s second law of motion, and explain the relationship between force, mass, and acceleration. State Newton’s third law of motion, and give examples of force pairs.

Agenda Today we will: Day 1 Take notes on Newton’s three laws Day 2 Group activity calculating Newton’s three laws. Individual activity answering questions about Newton’s laws. Exit ticket

Vocabulary Newton’s 3 laws inertia

Newton’s First Law of Motion An object at rest remains at rest, and an object in motion remains in motion at a constant speed and in a straight line unless acted on by an unbalanced force. Newton’s first law of motion describes the motion of an object that has a net force of 0 N acting on it.

Newton’s First Law of Motion Part 1: Objects at Rest Objects at rest will stay at rest unless they are acted on by an unbalanced force. Part 2: Objects in Motion Objects will continue to move with the same velocity unless an unbalanced force acts on them. The image on the next slide shows how you can have fun with Newton’s first law.

Newton’s First Law of Motion Friction and Newton’s First Law Friction between an object and the surface it is moving over is an example of an unbalanced force that stops motion. Inertia and Newton’s First Law Newton’s first law is sometimes called the law of inertia. Inertia is the tendency of all objects to resist any change in motion.

Newton’s First Law of Motion Mass and Inertia Mass is a measure of inertia. An object that has a small mass has less inertia than an object that has a large mass. So, changing the motion of an object that has a small mass is easier than changing the motion of an object that has a large mass.

Newton’s Second Law of Motion The acceleration of an object depends on the mass of the object and the amount of force applied. Newton’s second law describes the motion of an object when an unbalanced force acts on the object.

Newton’s Second Law of Motion Part 1: Acceleration Depends on Mass The acceleration of an object decreases as its mass increases. Its acceleration increases as its mass decreases. Part 2: Acceleration Depends on Force An object’s acceleration increases as the force on the object increases. The acceleration of an object is always in the same direction as the force applied.

Newton’s Second Law of Motion Expressing Newton’s Second Law Mathematically The relationship of acceleration (a) to mass (m) and force (F) can be expressed mathematically with the following equation: m a = F , or 

Newton’s Third Law of Motion Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Newton’s third law of motion can be simply stated as follows: All forces act in pairs.

Newton’s Third Law of Motion Force Pairs Do Not Act on the Same Object A force is always exerted by one object on another object. This rule is true for all forces, including action and reaction forces. Action and reaction forces in a pair do not act on the same object. If they did, the net force would always be 0 N and nothing would ever move!

Newton’s Third Law of Motion All Forces Act in Pairs—Action and Reaction Newton’s third law says that all forces act in pairs. When a force is exerted, there is always a reaction force.

Newton’s Third Law of Motion The Effect of a Reaction Can Be Difficult to See When an object falls, gravity pulls the object toward Earth and pulls Earth toward the object. You don’t notice Earth being pulled upward because the mass of Earth is much larger than the mass of the object. Thus, the acceleration of Earth is much smaller than the acceleration of the object.

Exit Ticket