CHAPTER 13 SECTION 1 FORCES EQ What is

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CHAPTER 13 SECTION 1 - FORCES EQ: What is the difference between balanced and

CHAPTER 13 SECTION 1 - FORCES EQ: What is the difference between balanced and unbalanced forces?

FORCE - a push or pull - causes an object to accelerate or change

FORCE - a push or pull - causes an object to accelerate or change motion - examples: magnet picking up a paperclip, hand throwing a ball

NET FORCE - the combination of all the forces acting on an object -

NET FORCE - the combination of all the forces acting on an object - determines the motion of an object -net force of zero means no motion

CALCULATING NET FORCE - if the objects are moving in the same directionadd the

CALCULATING NET FORCE - if the objects are moving in the same directionadd the forces - if objects are moving in opposite directionssubtract the forces. Object will move in direction of larger force

EXAMPLES OF NET FORCES 5 N 5 N 0 FORCE 5 N 3 N

EXAMPLES OF NET FORCES 5 N 5 N 0 FORCE 5 N 3 N 5 N 5 N + 3 N = 8 N RIGHT 5 N – 3 N = 2 N RIGHT 3 N

BALANCED FORCES - two or more forces whose effects cancel each other out and

BALANCED FORCES - two or more forces whose effects cancel each other out and do not change the motion of an object - net force is zero

UNBALANCED FORCES -two or more forces acting on an object that do not cancel,

UNBALANCED FORCES -two or more forces acting on an object that do not cancel, and cause the object to accelerate -motion of the object changes

Draw a representation of unbalanced force/Balanced force

Draw a representation of unbalanced force/Balanced force

CHAPTER 13 SECTION 1 FRICTION EQ: Compare and contrast the 3 types of friction.

CHAPTER 13 SECTION 1 FRICTION EQ: Compare and contrast the 3 types of friction.

NEWTON’S FIRST LAW OF MOTION - if the net force acting on an object

NEWTON’S FIRST LAW OF MOTION - if the net force acting on an object is zero, the object remains at rest -if the object is moving, it continues to move in a straight line with constant speed

FRICTION - a force that acts to resist sliding between two touching surfaces brings

FRICTION - a force that acts to resist sliding between two touching surfaces brings nearly everything to a stop there are different forms, but they always slow an object down

WHATS AN EXAMPLE OF FRICTION YOU KNOW OF?

WHATS AN EXAMPLE OF FRICTION YOU KNOW OF?

OLDER IDEAS ABOUT MOTION - they didn’t understand friction so they thought the natural

OLDER IDEAS ABOUT MOTION - they didn’t understand friction so they thought the natural state of objects was at rest - reality: friction stops things, if friction could be removed, an object in motion would continue in a straight line with constant speed

STATIC FRICTION - prevents an object from moving when a force is applied -

STATIC FRICTION - prevents an object from moving when a force is applied - caused by attraction between atoms on two surfaces that are in contact - you need to exert a force large enough to break the bond holding surfaces together - keeps an object at rest

SLIDING FRICTION - slows down an object that slides - due to roughness of

SLIDING FRICTION - slows down an object that slides - due to roughness of two surfaces - example: brake pads on a car rub against the wheels to slow it down

ROLLING FRICTION -occurs between the ground and the part of the tire touching the

ROLLING FRICTION -occurs between the ground and the part of the tire touching the ground - it is needed to make a wheel or tire turn - keeps tires from slipping on the ground