Contact vs.

NoncontactFORCES

Distinguish between contact and noncontact forces.

Explore the Law of Gravity by recognizing that every object exerts a gravitational force.

OBJECTIVES

ESSENTIAL QUESTIONWhat forces may hinder the motion of a

soccer ball rolling across a field?

AGENDA• Bell Ringer• PowerPoint with Notes• Brain Pop with Review Quiz: Gravity• Check for Understandings• Mini Book Activity• Independent Practice

Contact ForceA force that can

cause or change motion of an object by touching it. Motors and gears operate through contact forces.

Non-Contact Force

Force that results when the two objects are not in physical contact with each other, yet are able to exert a push or pull.

FORCE: A PUSH OR PULL

Contact Force Examples: • Friction• Normal Force• Air Resistance• Applied Force

Non-Contact Force Examples: • Gravitational

Force• Electrical Force• Magnetic Force

Applied Force: A force typical push or pull, pushing a door open, pulling a rope.

Friction: Happens when two objects rub against each other. Friction opposes motion.

Normal Force: The normal force is the support force exerted upon an object that is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book.

Air Resistance: The air resistance is a type of frictional force that acts upon objects as they travel through the air.

CONTACT FORCES

CONTACT FORCES

Normal Force= 10N

Magnetic Force: A kind of non contact force, materials such as iron, nickel, cobalt and other magnets just need to be near the magnet to be attracted or repelled.

Electric Force: Noncontact force of electrical charges.

Gravitational Force: The force of attraction between any two objects in the universe . All objects have gravitational force. The mass of an object and its distance determines the strength of its gravitational force.

NON-CONTACT FORCES

GRAVITYMass and distance affect the force of gravity. The greater the mass and the closer the object, the stronger its gravitational pull.

GRAVITY

The force of gravity between two objects depends on two factors:

Mass Distance

*Longer arrows represent a greater force of gravity.

How does the force of gravity change as the mass of objects and distance between them changes?

The amount of matter in an object.

Unit: GramsDoes not depend of

gravity. Measured with a triple

beam or digital balance.

Measure of the Earth’s gravitational pull (a force).

measured in lbs. or N

Changes depending on the gravitational force.

Measured using a spring scale.

MASS VS. WEIGHT

BRAIN POP: GRAVITY

Quiz Afterwards!

A foot kicking a soccer ballAn apple falling off a treeA paper clip sliding towards a magnetA bat striking a baseballTwo magnets pushing apart from one another

The moon orbiting the EarthA compass needle turning NorthA hand pushing an objectShoes rubbing against the floor

CLASSIFY THE FORCES

Now that we have learned about forces, lets talk about the essential question! You will answer the EQ on the front of your foldable.

DISCUSS!

ESSENTIAL QUESTION

What forces may hinder the motion of a soccer ball rolling across a field?

Make a Book!

Front Cover: “Force: A Push or Pull”Your name and the period.

Page 1: Contact Force

Page 2: Examples

Page 3: Non Contact Force

Page 4: Examples

Page 5: Gravity

Page 6: Summary

Time to tap into some creativity! You will create a 6-page book that covers what you learned today.

(10 minutes)

INDEPENDENT PRACTICE