motion: describing and measuring motion
DESCRIPTION
MOTION: Describing and Measuring Motion. CHAPTER 10. Measuring Motion. Motion is described as a change in position An object is considered in motion when observed in relation to a REFERENCE POINT. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/1.jpg)
MOTION: Describing and Measuring
Motion
CHAPTER 10
![Page 2: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/2.jpg)
Measuring MotionMotion is described as a change in positionAn object is considered in motion when observed in relation to a REFERENCE POINT.Describe motions with reference terms such as: north, south, east, west, up, down, right, left, etc.
![Page 3: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/3.jpg)
Frame of ReferenceThe object or point from which movement is determinedAny object can appear to be in motion or at rest depending on the frame of reference of the observer.
Motion can only be determined when there is a frame of referenceEarth is the most commonly used frame of reference
![Page 4: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/4.jpg)
Frame of Referenceand Relative Motion
Example: When you are standing on the ground, that is your frame of reference. Anything you see, watch, or measure will be compared to the reference point of the ground.
Relative Motion is based on the person describing the motion based on their frame of reference.
![Page 5: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/5.jpg)
Frame of Reference
Frame of Reference for theSkydiversa. Plane – in motion away from themb. Themselves – not in motionc. The ground – in motion towards them
Frame of reference for 2 girls…Red Dress Girl uses the moving vehicleAs her frame of reference and is notMovingYellow Dress girl uses her frame of Reference as a stationary position to See the other girl in motion.
![Page 6: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/6.jpg)
Example 1:Sitting at your desk, how fast are you moving?– Relative to the ground: ZERO
– Relative to the sun: 2.97 X104 m/s! An observer standing on the sun would say you are moving at 2.97 X104 m/s
![Page 7: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/7.jpg)
Example 2:While sitting at a red light a bus stops in the lane next to you…as you are daydreaming looking at the side of the bus…you all of a sudden feel like you are rolling backwards Then you realize it is the bus moving forwards when you take into account a stationary frame of reference.This is your brain “confused”
![Page 8: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/8.jpg)
Did you know?Motion Sickness is caused by your brain getting two different sets of information about your body’s motion based on its frame of reference, the information from your eyes and the information from your inner earTo help with motion sickness, try to look forward at a point far in the distance and stay focused on that.
![Page 9: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/9.jpg)
Distance vs. DisplacementDistance• Scalar (amount only)• Direction does NOT matter.• The actual path
matters!• The total distance traveled.
• In the Daytona 500, the cars travel a distance of 500 miles.
Displacement• Vector (amount and
direction)• Direction DOES matter!• The path does NOT
matter!• The straight-line distance
(and direction) the object has travelled from its starting point.
• In the Daytona 500, the cars experience zero displacement (they start where they end).
![Page 10: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/10.jpg)
Distance vs. DisplacementWhat is the overall distance traveled in the picture below? What is the overall displacement in the picture below?
START
Leg 1
Leg 3
Leg 2
End
Leg 1 Distance = ______Leg 1 Displacement = _____
Leg 2 Distance = ______Leg 2 Displacement = _____
Leg 3 Distance = ______Leg 3 Displacement = _____
Final Distance = ______Final Displacement = _____
![Page 11: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/11.jpg)
Distance vs. Displacement
![Page 12: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/12.jpg)
Vector DiagramsThe objects motion is represented with an arrow in the direction traveling. The size of the arrow indicates the relative speed of that object.
![Page 13: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/13.jpg)
Practice with Frames of Reference / Distance and
DisplacementPracticeWorksheet as a class fun with mapping … check out Santa’s route to your house!
![Page 14: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/14.jpg)
Speed and Velocity
A little lesson through music
![Page 15: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/15.jpg)
SPEEDSPEED – the rate of change in position or rate of motionINSTANTANEOUS SPEED – Rate of motion at any given instant – (ex: speedometer in a car)
CONSTANT SPEED – A speed that does not vary – (ex: cruise control)
– Usain Bolt races at ESPN video clip– Usain Bolt Olympics
![Page 16: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/16.jpg)
Constant Speed vs. Instantaneous Speed….Let’s graph
![Page 17: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/17.jpg)
CALCULATING SPEEDWhen we calculate speed, we are calculating the average speed traveled.AVERAGE SPEED – a measure of total distance traveled divided by total time of travel
SPEED (v) = DISTANCE (d)TIME (t)
UNITS FOR SPEED ---- m/s
![Page 18: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/18.jpg)
DISTANCE-TIME GRAPHThe distance covered by an object is noted at regular intervals of time.
![Page 19: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/19.jpg)
Measuring SpeedSport Science - John WallSport Science - Lebron JamesSport Science - Ndamukong Suh
![Page 20: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/20.jpg)
VELOCITYVELOCITY – Describes both speed AND direction.Velocity can change even if the speed of the object does not change.Calculating Velocity:– Velocity = Displacement / time – Answers will include direction
![Page 21: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/21.jpg)
Velocity – Time GraphA velocity – time graph can show acceleration.
![Page 22: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/22.jpg)
Distance-Time Graphvs.
Velocity Time GraphShows velocity of object, time.Can calculate Acceleration
Shows Motion, distance traveled, and time.Can calculate speed.
![Page 23: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/23.jpg)
ACCELERATIONACCELERATION – The rate of change of velocity.Acceleration can be a change in speed OR direction
Circular motion is a constant acceleration– Example: blades of a fan
![Page 24: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/24.jpg)
Acceleration…Let’s graph
![Page 25: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/25.jpg)
Constant Velocity = Zero Acceleration
![Page 26: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/26.jpg)
Positive Velocity = Positive Acceleration
![Page 27: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/27.jpg)
CALCULATING ACCELERATION
Divide the change in velocity by the time interval
Acceleration (a) = (final velocity – initial velocity)
time intervala = (vf – vi)
t* Unit for Acceleration: m/s2 (plus
direction)
![Page 28: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/28.jpg)
Acceleration PracticeNatalie accelerates her skateboard along a straight path from 0 m/s to 4.0 m/s in 2.5 seconds. Find her average acceleration.
a = 4.0 m/s – 0 m/s2.5 s
a = 1.6 m/s2 along her path
* Practice: p. 328 # 2-5
![Page 29: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/29.jpg)
Example: Positive Acceleration
Acceleration = (30 m/s – 0 m/s)/10 s a = 3 m/s/sThe car’s acceleration is increasing 3 m/s2
![Page 30: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/30.jpg)
Examples: Negative Acceleration
a = (0m/s – 20 m/s)/10 s a = - 2 m/s/sThe cars acceleration is decreasing at 2 m/s2
![Page 31: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/31.jpg)
MOTION AND FORCEFORCE – A push or a pull one object puts on another.BALANCED FORCE – Forces that are equal in size and opposite in direction.UNBALANCED FORCE (NET FORCE) – Forces that are unequal in size…Cause a change in motion.– Unbalanced forces always change the
velocity of the object.
![Page 32: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/32.jpg)
Balanced vs. Unbalanced Forces
Balanced Force opposite in direction - pulling
Balanced force pushing on each other
Unbalanced forces….showing displacement of the object
Unblalanced Forces – adding up to displace the object in one direction
![Page 33: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/33.jpg)
![Page 34: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/34.jpg)
Forces that Act on Objects1. Normal Force – A support force when one object is in contact with a stable object (ex: Book on a table)2. Tension Force – A force transmitted through a string, rope, or cable3. Gravitational Force – The force of attraction to a very large object in the universe4. Friction Force – The force that opposes motion between two surfaces.
![Page 35: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/35.jpg)
Normal Force vs. Gravity Force
![Page 36: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/36.jpg)
Tension Force
![Page 37: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/37.jpg)
Friction Force
![Page 38: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/38.jpg)
FRICTIONFRICTION – The force that opposes motion between two surfaces that are touching each other.2 TYPES OF FRICTION:– STATIC FRICTION – The friction between
surfaces that are stationary.– KINETIC FRICTION – The friction between
moving surfaces.Kinetic Friction can be SLIDING or ROLLING
![Page 39: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/39.jpg)
Increasing or Decreasing FrictionIncrease Friction by using rough surfaces – EX: Cleaning surfaces with a rough
spongeDecrease Friction by adding a liquid– Ex: Oil, WD40
![Page 40: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/40.jpg)
Gravity and Force
![Page 41: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/41.jpg)
Gravity is a Field ForceAll objects in the universe have a gravitational force. Larger objects exert more force than smaller objects.
![Page 42: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/42.jpg)
Calculating Gravitational ForceGravitational force (weight) of an objects is proportional to its massForce (gravity) = (mass) (gravity)– Acceleration due to Gravity (g) is equal
to 9.8 m/s2
![Page 43: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/43.jpg)
Newton’s Second LawAn unbalanced force acting on an object causes that object to change speed or directionAcceleration = Force / Mass
![Page 44: MOTION: Describing and Measuring Motion](https://reader035.vdocuments.us/reader035/viewer/2022062223/568163ce550346895dd5121a/html5/thumbnails/44.jpg)
Action - ReactionEvery action has an equal and opposite reaction.Example: The truck hits the sign therefore the sign hits the truck with an equal force in the opposite direction.