Isaac Newton explained this relationship between force and the motion of an object.

Law of Inertia Inertia is the tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction until an outside force acts on the object.

Law of Inertia Because of Inertia, an object at rest will stay at rest unless acted on by an unbalanced force. In other words, objects will not start moving until a push or a pull is exerted on them.

Law of Inertia

Law of Inertia An object in motion will remain in motion unless acted on by an unbalanced force. The object will continue to move in the same direction with the same speed unless an unbalanced force occurs.

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 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.

The car because it has more mass therefore more inertia. Mass and Inertia Look at the images below. Which would require more force to move or slow down? Why? The car because it has more mass therefore more inertia.

Mass and Inertia Which would require more force to move or slow down? Why? The bowling ball because it has more mass therefore more inertia.

The snowboard is in motion The snowboard is in motion. Based on the Law of Inertia, the snowboard will keep moving right? What force(s) allow him to snowboard on the brick wall and rail?

Newtons’s 1st Law of Motion Friction and the Law of Inertia Objects in motion remain in motion unless acted on by an unbalanced force. Friction is often the unbalanced force that causes objects to slow down and stop moving. Because of friction, the motion of objects changes.

Newton’s First Law of Motion: Inertia

Balanced Force Equal forces in opposite directions produce no motion

Unbalanced Forces Unequal opposing forces produce an unbalanced force causing motion

Force equals mass times acceleration. Newton’s Second Law Force equals mass times acceleration. F = ma

WEIGHT is a measure of the force of ________ on the mass of an object Newton’s Second Law WEIGHT is a measure of the force of ________ on the mass of an object measured in __________ gravity Newtons

For every action there is an equal and opposite reaction. Newton’s Third Law For every action there is an equal and opposite reaction.

Newton’s 3rd Law For every action there is an equal and opposite reaction. Book to earth Table to book

Think about it . . . What happens if you are standing on a skateboard or a slippery floor and push against a wall? You slide in the opposite direction (away from the wall), because you pushed on the wall but the wall pushed back on you with equal and opposite force.

Action: tire pushes on road Reaction: road pushes on tire

Reaction: gases push on rocket Action: rocket pushes on gases

(a) the force applied to the bat by the hands Consider hitting a baseball with a bat. If we call the force applied to the ball by the bat the action force, identify the reaction force. (a) the force applied to the bat by the hands (b) the force applied to the bat by the ball (c) the force the ball carries with it in flight (d) the centrifugal force in the swing (b) the force applied to the bat by the ball

What Laws are represented?

Review 1) Newton’s First Law: Objects in motion tend to stay in motion and objects at rest tend to stay at rest unless acted upon by an unbalanced force. 2) Newton’s Second Law: Force equals mass times acceleration (F = ma). 3) Newton’s Third Law: For every action there is an equal and opposite reaction.

Study Jams: Newton’s Second Law Acceleration

Study Jams: Newton’s Third Law