Chapter 1; Section 1

Road Runner VideoNotes:

Observing MotionReference Point:

Object that appears to stay in placeEx: Earth’s surface

YouLandscape

Motion: When an object changes position over

time when compared with a reference point

Dancing on the Ceiling

Fred Astaire’s Dance

Speed Depends on Distance and TimeSpeed: The rate an object moves

How long it takes an object to move over time

Average Speed= total distance/ total time

SI unit for speed= meters per second (m/s)

Activity: Math Break pg 5

Velocity: Direction MattersVelocity: The speed of an object in a specific

directionPlanes velocity = 600 km/h south

Activity: Self Check pg 6

Change in velocity= change in speed or direction

Combining VelocitiesCombine two velocities in same direction= add

togetherCombine two velocities in opposite directions=

subtract smaller velocity from larger velocity

Section Review Pg 7

Acceleration

Acceleration ContinuedCircular motion: Continuous Acceleration

Centripetal Acceleration= Change direction in a circle, changes velocity

Figure 5

Graphing Acceleration:Acceleration= positive because velocity

increases as time passes (Graph goes up)Deceleration= Graph goes down

Section Review Pg 10Answers on pg 10 in book

What is Force?Chapter 1 Section 2

Forces Act on ObjectsForces= A push or pull on an object

Size and direction

Newton= How force is measuredSI unit

Activity:Examples

Forces in CombinationNet Fore= The combination of forces on an object

May the Force Be With You

Forces in the same direction= Added Together

Forces in the opposite direction= Subtracted from one anotherSubtract the smaller force from the larger

Figure 8:Pg 13 Self Check:

Unbalanced and Balanced ForcesUnbalanced Forces=

The object moves (Change in motion)Net force NOT EQUAL to 0 NEx. Soccer Ball

Balanced Force= the object doesn’t move

Net force EQUAL to 0 NEx. Bird’s nest in a treeEx. Hat resting on your head

Friction: A Force That Opposes Motion

Chapter 1, Section 3

The Source of FrictionFriction: A force that opposes motion

between two surfaces that are touching.Friction depends on two things:

1. Roughness of surfaces- The rougher the surface, the more friction

Ex. Skating on ice vs. grass

2. Amount of force- the greater the force the more friction

Ex. Massive object vs. Non massive object

Activity:Pg 15: Connect to life…

Types of FrictionDefinitionTwo facts3 examples

Types of FrictionSliding Friction- The friction of sliding an

object across another object.Ex. Sliding a dresser on the floor or sledding down a hill

Rolling Friction- The friction between wheels and the surface they are rolling onEx. Pushing a grocery cart or roller skating

Fluid Friction- The friction opposes the motion of objects traveling through a fluid (fluid may be gas or liquid)Ex. Swimming through water or a plane flying in the air

Static Friction- Friction that keeps an object stationaryEx. Pushing on a wall

Discussion!Ways to reduce friction?

Ways to increase friction?

Activity:pg 20 apply

Friction Can Be Harmful or Helpful

Harmful frictionHoles in socks or knees of jeansWind & water cause erosion

Helpful frictionFriction between pencil & paperWithout friction, you would just slip & fall

when you tried to walk

Friction ReductionWays to reduce friction

Lubricants- Substances applied to surfaces to reduce the friction between them

Switching from sliding friction to rolling friction by the use of ball bearings

Make surfaces that rub together smoother

25

Gravity: A Force of Attraction

Chapter 1, Section 4

Gravity

All Matter Is Affected by GravityGravity = The force between two objects due

to their massesAll objects experience an attraction toward

all other objectsEarth’s gravitational force is large= pulls

everything toward center of earthEx. Chair stays in placeEx. Dropped objects fall to earth and not

toward you

The Law of Universal GravitationSir Isaac Newton

Law= All object attract each other and the force depends on the objects mass and distance

Gravitational force increases when mass increasesEx. Cat is easier to pick up than elephant

Gravitational force decreases when distance increasesEx. PlanetsActivity:Pg 24 Activity

Weight Is a Measure of Gravitational Force

Weight= A measure of the gravitational force exerted on an object

Mass= Amount of matter in an object (value does not change)

Gravity is a force and is measured in Newton's

100 g is about 1 N