Describing MotionDescribing MotionChapter 1 - Section 1 Chapter 1 - Section 1

NotesNotesP: Identify the properties of objects that are in motion

Q: How can an object be moving but not be in motion?

DefinitionsDefinitions

• An object is in An object is in MOTIONMOTION if its distance from if its distance from another object another object is changingis changing

• Reference pointReference point a place or object used a place or object used for comparison to determine if something for comparison to determine if something is in motionis in motion

• In other words…In other words…An object is An object is IN MOTIONIN MOTION when it changes position relative to a when it changes position relative to a REFERENCE POINTREFERENCE POINT..

Reference PointsReference Points

• Good Reference PointsGood Reference Points = = stationary stationary objects objects – (ex: tree, sign, building)(ex: tree, sign, building)

• Bad Reference PointsBad Reference Points = any = any moving moving object object – (ex: a moving car, a flying plane)(ex: a moving car, a flying plane)

Types of MotionTypes of Motion

• Straight lineStraight line

• ProjectileProjectile

• CircularCircular

• VibrationalVibrational

Straight Line MotionStraight Line Motion

• Occurs when an object moves in a Occurs when an object moves in a STRAIGHT LINE STRAIGHT LINE – (ex: a moving car, plane or bicycle)(ex: a moving car, plane or bicycle)

Projectile MotionProjectile Motion

• Occurs when an object is thrown or projectedOccurs when an object is thrown or projected– Moves in an arc/parabolaMoves in an arc/parabola

•Ex: a shooting cannon ball, arrow from a bow, Ex: a shooting cannon ball, arrow from a bow, or a baseball pitchor a baseball pitch

Circular MotionCircular Motion

• Occurs when an Occurs when an object spins/turns object spins/turns on its axison its axis– Ex: Earth, a top, a Ex: Earth, a top, a

Ferris wheelFerris wheel

Vibrational MotionVibrational Motion

• Occurs when an Occurs when an object moves back object moves back and forth rapidlyand forth rapidly– Ex: Sound waves, Ex: Sound waves,

tuning forks, guitar tuning forks, guitar strings, vocal strings, vocal chords, etc.chords, etc.

Relative MotionRelative Motion

• Whether or not an object is in motion Whether or not an object is in motion depends on the depends on the reference pointreference point you you choose!choose!(See (See PAGE 8PAGE 8 in your textbook) in your textbook)

*Are the skydivers in motion relative to *Are the skydivers in motion relative to each other?each other?

*Are they in motion relative to the *Are they in motion relative to the airplane from which they jumped?airplane from which they jumped?

*Are they in motion relative to the *Are they in motion relative to the ground?ground?

Consider this…Consider this…

• Is it possible to be Is it possible to be movingmoving, ,

but NOT be but NOT be in motionin motion??

LOL _________________________LOL _________________________

1) ExplainExplain how an object can be moving but not be in motion. (Use the terms relative motionrelative motion

and reference pointreference point in your explanation.)

2) Compare and contrast Compare and contrast the 4 types of motion.

3) ListList 4 examples of objects that you observe in motion today/tonight. (Find at least 11 examples of each typeeach type). What is the reference point in each example?

LOL(LOL(ChallengeChallenge)__________________)__________________

1) ExplainExplain how an object can be moving but not be in motion. (Use the terms relative motionrelative motion

and reference pointreference point in your explanation.)

2) Compare and contrast Compare and contrast the 4 types of motion.

3) ListList 8 “real life” examples of objects that you observe in motion today/tonight. (Find at least 22 examples of each typeeach type)