SNB page 43

 gravity  law of universal gravitation  weight  friction  elastic force  tension force  compression force  normal force

 Gravity is an attractive force between all objects that have mass.  The ball does not travel in a straight line because of the unbalanced force of gravity acting on it.

 The Law of Universal Gravitation states that all objects with mass are attracted to each other.  The magnitude of attraction depends on the mass of each object and the distance between them.

 If you drop one ball and shoot the other out to the side, which one will hit the ground first? 

2.2 Types of Forces

 Friction is a force that opposes the movement between two surfaces in contact.  Static friction is the force between two surfaces in contact that keeps them from sliding when a force is applied.  The frictional force that acts on the sliding object is called sliding friction.  Static friction prevents the surfaces from sliding past each other.  Sliding friction exists when surfaces are sliding past each other.

 An elastic force occurs when a material is stretched or compressed. A diving board exerts an upward elastic force on the diver when it is bent downward. 2.2 Types of Forces

 A tension force is a pulling force applied by an object when it is stretched, such as a rubber band.  A contact force that occurs when an object is stretched.

 A compression force is a squeezing force applied to an object that can make an object shrink. A contact force that occurs when an object is squeezed. 2.2 Types of Forces

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 A normal force is the force exerted by an object that is perpendicular to the surface of the object.  The normal force exerted by the table is an elastic force.  The weight of the glass pushing down on the table is a compression force. 2.2 Types of Forces

1. Follow Mr. Klimenko’s instructions to fold. 2. Label the tabs as – Force of Gravity, Force of Friction, Tension Force, Compression Force, Normal Force and Centripetal Force 3. Write the definition behind each tab, and write or draw an example under the tab.

Describe the following answers as a Force of Gravity, a Static Friction or a Sliding Friction. 1. A rider stops pedaling so the bike slows down. 2. You give the table a small push, but it does not move. 3. You throw a ball straight but it starts to bend downward and drops.

SNB page 3

 Mass is the amount of matter in an object and does not change with location. Weight is the gravitational force on a object and changes with location. 2.2 Types of Forces Weight is a force and a vector. Weight changes with height above Earth.

 Where will a 20g piece of gold weigh more? 1) San Francisco, CA – At Sea Level 2) Denver, CO – 5,300 above Sea Level

 The Law of Universal Gravitation states that all objects with mass are attracted to each other.  The magnitude of attraction depends on the mass of each object and the distance between them.

 The gravitational force becomes stronger as either or both objects increase in mass. The gravitational force becomes weaker as the distance between the objects increases. 2.2 Types of Forces

 What is an example of a gravitational force acting on an object to change its direction?

 The gravitational force between two objects ____ as ____ increases. 1) increases; distance 2) decreases; mass 3) increases; velocity 4) decreases; distance

 If you drop one bullet and shoot the other out of a gun, which one will hit the ground first? 

2.2 Types of Forces

 Friction is a force that opposes the movement between two surfaces in contact.  Static friction is the force between two surfaces in contact that keeps them from sliding when a force is applied.  The frictional force that acts on the sliding object is called sliding friction.  Static friction prevents the surfaces from sliding past each other.  Sliding friction exists when surfaces are sliding past each other.

What type of friction is this an example of?  You roll a ball and then it slows and comes to a stop. 1) Static Friction 2) Sliding Friction 3) Gravity

 Friction balances forces applied in a horizontal direction. Friction equals the horizontal force on an object that is not changing motion. 2.2 Types of Forces

 Upward normal force balances the downward force of gravity on an object that is not moving vertically. 2.2 Types of Forces

1. Follow Mr. Klimenko’s instructions to fold. 2. Label the tabs as – Force of Gravity, Force of Friction, Elastic Force, Tension Force, Compression Force, and Normal Force. 3. Write the definition behind each tab, and write or draw an example under the tab. 4. The foldable is to be competed today.

Describe the following answers as a Elastic Force, a Tension Force, Compression Force or a Normal Force. 1. A 2. You 3. You