 Describing Motion.

Presentation on theme: "Describing Motion."— Presentation transcript:

Describing Motion

Motion Starter #2 Work as a group of 4 at your table and “play” with the battery operated toy cars. Use any additional materials you might need – meter stick, tape, timer, wood blocks etc. PLEASE USE THEM ON THE FLOOR NOT ON THE TABLES! Describe the motion of these toys. Write your description on a sticky note and put it on the board when finished.

Motion Starter What words did you use to describe the motion? Share the sticky notes.

Describing Motion Describe the motion of these wind-up toys.
How far does it move? How fast does it move? Does it move at a steady rate, speed up, or slow down?. What direction does it move? These all describe MOTION.

Measuring Motion As a table group come up with definitions for OR drawings to show Distance vs. Displacement Be sure to clearly show the difference between the two! Write your definitions/draw pictures on 2 different sticky notes and put them on the board.

Measuring Motion DISTANCE DISPLACEMENT

Measuring Motion Distance – total change in position Displacement –
position IN A STRAIGHT LINE (from point A to point B)

A B

Motion song

What is Motion Video

TRY THIS! Is your desk in motion?
We need a reference point… Define Reference Point: nonmoving point from which motion is measured

TRY THIS! Is your desk in motion?
From the reference point of your seat is you desk in motion?

TRY THIS! Is your desk in motion?
From the reference point of your seat is you desk in motion? NO!

TRY THIS! Is your desk in motion?
From the reference point of space, is your desk in motion?

TRY THIS! Is your desk in motion?
From the reference point of space, is your desk in motion? YES!

Reference Point Define Motion: Reference point Motion

Reference Point Define Motion
A change in position in relation to a reference point. Reference point Motion

Frame of Reference VIDEO 2 1) DESCRIBE THE MOTION OF THE BALL FROM THE POINT OF VIEW OF THE AUDIENCE. 2) DESCRIBE THE MOTION OF THE BALL FROM THE POINT OF VIEW OF THE CART FROM WHICH IT IS SHOT.

Frame of Reference VIDEO 1 11

Frame of Reference VIDEO 3 11

Frame of Reference VIDEO 4 11
DESRCRIBE THE MOTION OF THE ORANGE FROM THE POINT OF VIEW OF A PERSON STANDING ON THE TRAIN DESCRIBE THE MOTION OF THE ORANGE FROM THE POINT OF VIEW OF SOMEONE WATCHING THE TRAIN PASS BY THEM ON THE STREET.

MEASURING DISTANCE & DISPLACEMENTS

DESCRIBING MOTION EXIT TICKET
What is a frame of reference and how is it used to measure motion? How are distance and displacement similar and different? How are displacements combined? A girl who is watching a plane fly tells her friend that the plane isn’t moving at all. Describe a frame of reference in which the girl’s description would be true. Would your directions to a friend traveling from one city to another include displacements or distances? Explain.

Frame of reference is a set of objects that are not moving with respect to one another. Motion can only be describe in comparison to a frame of reference. Distance is the length of an object’s actual path from a starting point to an ending point. Displacement is the length of a straight line from the starting point to the ending point. Displacements are combined using vector addition.

4. If the plane is far away and flying directly toward or away form the girl, the plane would appear not to be moving. Also, the plane would not be moving int eh frame of reference of the people on the plane.

Quick Lab Do the Lab on page 330 in your textbook
Use the graph paper on the other side of your Motion Exit Ticket. Exchange your paper with a partner when you’re finished. Determine the distance and displacement of their path ASSESS: Draw a shape with a distance of 10 and a displacement of 0

Complete the “Skate Park” challenge
Speed starter Complete the “Skate Park” challenge

Speed Speed – the rate at which an object changes its position
What is your speed if you cover 240 miles in 4 hours? Never Fear! Equation person is here!

S = d/t What is your speed if you cover 240 miles in 4 hours?

s d t S = d/t What is your speed if you cover 240 miles in 4 hours?
S = 240/4 = 60 mi/hr!!

DISTANCE: Miles, Feet, Meters SPEED: Miles/Hour, Feet/Second, Meters/second Units are CLUES!

Try This! What is the speed of a car moving 124 miles in 2 hours? (SHOW EQUATION, correct answers, and units!) 124 miles = DISTANCE 2 hours = TIME Solve for SPEED!

ANSWER S = d/t 124/2 = 62 mi/hr (mph) s d t

MEASURING SPEED Measure distance in meters, miles, kilometers Measure time in seconds, hours, Measure speed in m/s, mph, m/h, km/h

Now it’s time for a LAB!! Take a Walk in the Park!

Let’s practice! s d t

During a trip, you have… Average speed your average speed over the whole trip Instantaneous speed your speed at any given instant during the trip

Average speed your average speed over the whole trip
Instantaneous speed your speed at any given instant during the trip You travel from Columbus to Cincinnati (220 miles) in 4 hours. What is your speed? Did you have this speed throughout the entire trip? What was your instantaneous speed at a stop sign?

Average speed your average speed over the whole trip
Instantaneous speed your speed at any given instant during the trip You travel from Columbus to Cincinnati (220 miles) in 4 hours. What is your speed? Did you have this speed throughout the entire trip? NO! It’s your AVERAGE speed. What was your instantaneous speed at a stop sign?

Average speed your average speed over the whole trip
Instantaneous speed your speed at any given instant during the trip You travel from Columbus to Cincinnati (220 miles) in 4 hours. What is your speed? Did you have this speed throughout the entire trip? NO! It’s your AVERAGE speed. What was your instantaneous speed at a stop sign? 0 m/h

Back to Equation Person!
S = d/t What type of speed are you calculating with this equation? Instantaneous or Average?

Back to Equation Person!
S = d/t What type of speed are you calculating with this equation? Instantaneous or Average?

What is the car’s AVERAGE speed?

Then let’s practice calculating Average Speed
Speed Formula Song! Then let’s practice calculating Average Speed

A storm is 10 km away and is moving at a speed of 60 km/h
A storm is 10 km away and is moving at a speed of 60 km/h. Should you be worried?

A storm is 10 km away and is moving at a speed of 60 km/h
A storm is 10 km away and is moving at a speed of 60 km/h. Should you be worried? It depends on the storm’s direction!

Velocity Velocity is speed with a DIRECTION. Example:
70 mph is a speed (a scalar qty) 70 mph North is a velocity (a vector qty)

Calculating Velocity Average Velocity = change in position time
V = position = displacement time time Remember: displacement is the total change in position in a straight line from point A to point B This symbol means “a change in”

What is Earth’s Velocity?
Earth rotates 25,488 miles counterclockwise in 24 hours. SHOW EQUATION, ANSWER, UNITS!

Wait, the Earth has Velocity?

ANSWER V = d/t with direction 25,488/24 = 1062 mi/hr THAT’S FAST!
Counter-clockwise THAT’S FAST!

Let’s Finish the “Walk in the Park” lab

Let’s practice Speed & Velocity (homework on 9/4)

Changing Velocity Sometimes objects CHANGE velocity as they move. Example: Roll car down a ramp. How is its velocity CHANGING? This is known as ACCELERATION!

Acceleration Demo

Acceleration Acceleration is a change in VELOCITY due to a change in direction or speed. Speed up Slow down Change direction

Three Examples of Acceleration

ACCELERATION IS A RATE OF CHANGE in velocity!!
What is the acceleration of the car between 0 seconds and 2 seconds?

Equation Person Returns!
Your engine shuts off and you slow down from 60 mph to 0 mph in 3 seconds. What is your acceleration? What are the units of your acceleration? a: acceleration vf: final velocity vi: initial velocity t: time

t a ANSWER vf - vi A = 0 – 60 3 -20 mi/hr/sec a: acceleration
vf: final velocity vi: initial velocity t: time

NEGATIVE Acceleration??
Positive acceleration “speeding up” Negative acceleration “slowing down” That makes sense, since we went from 60  0 !!

A = Vf – Vi T Vf = 8m/2sec = 4m/s Vi = 0 m/s T = 2 sec A = 4-0 = 2 m/s/s or 2 m/s2

Ticker-Tape Machine Lab
Let’s practice! Acceleration Then, Time for a LAB!! Ticker-Tape Machine Lab