Motion and Speed

Flash Card

• On the front:

• Physics

• On the back:

• The branch of science that deals with matter, energy, space, time, and the relationship between them.

Warm-up 1/22/13

• Teach the Teacher: Who do you miss the most and why? • Review: What 4 things does physics

cover?

Physics Matter!

• http://www.nsf.gov/news/special_reports/olympics/bobsled.jsp

Flash Card

• On the front write:

•Motion

• On the back write:

• a change of position of an object.

Sec. 1 Describing Motion•Motion occurs when an object changes position.•You don’t need to see something move to know that motion has taken place.• You just need a reference point to know if

motion occurred

Distance and Displacement•Distance—how far an object moved• The SI unit for distance is the meter, m•Displacement—the distance and direction

of an object’s change in position from the starting point.

What is Speed? • Rate—any change over time• Speed—the distance an object travels per

unit of time.

fastest

Calculating Speed

• The speed of an object can be calculated from this equation:

• Speed = Distance

Time

S=D/T

• When working equations• Write the formula• Plug in the values for each known• Calculate the answer• Write the answer and a unit

D

S T

multiply

divide

Graphing Motion• On a distance vs. time graph, time goes on

the x-axis and distance goes on the y-axis.• The slope (steepness) of the line represents

the speed of the object.

Distance

Time↑

Speed

Draw this on your paper!

slowerfaster

Time (seconds)

Dis

tanc

e (m

eter

s)

Standing still

X-axis

Y-axis

Warm-up 1/23/2013

• Teach the Teacher: If your life song or theme song, what song would it be (that I want to know about)? • Review: Tell me anything you can about

motion.

Flash Card

• On the front write:

•Reference Point

• On the back write:

• Determines an object’s position and if motion happened

• Which one is the fastest?• Which one isn’t moving?

Distance Time Graphs

• What information is recorded on the x-axis?

• In what units is distance measured on the graph?

• The graphs represent three swimmers, What does the slope of the lines tell you about the swimmers?

• Which swimmer swam the fastest?

• Which swimmer stopped for 10 minutes?

• How far did the blue swimmer travel in 15 minutes?

What are the fastest animals (mph)?

1. Cheetah 70

2. Pronghorn antelope 61

3. Lion 50

4. Thomson's gazelle 50

5. Wildebeest 50

6. Springbok 50

7. Quarter horse 47.5

8. Cape hunting dog 45

9. Elk 45

10.Snail 0

The real world graphing…

• The Band is on the Field!

Average & Instantaneous Speed•Average speed—the total distance

traveled divided by the total time of travel.• Used when speed is changing

• Instantaneous speed—the speed at a given point in time.• Ex. Speedometer

Modeled off of Minute to Win It

PHYSICS TO

WIN IT! YOUR CHANCE TO WIN….

AND LEARN PHYSICS

Physics To Win It Challenge (PTW): Match the Graph • Use the CBR to make a distance vs. time graph, the

person who matches the graph exactly, within 5 tries, and answers these questions correctly gets a signature/stamp (THIS IS NOT TIMED) (I MUST SEE EVERYONES GRAPH)• Draw the Graph you matched perfectly..w/ labels• 1. What information is on the x-axis? What information

is on the Y-axis• 2. What did you do when the line was flat (or horizontal)? • 3. Should you walk forward or backward for a segment

that slopes up?

Calculator-Based Ranger

• 200 samples per second with a range between 0.5 meters and 6 meters• (1.5 feet and 18 feet)• better results with a relatively hard, smooth

surface (aim for gold sheet) • You break you buy (cords are delicate!)

Velocity• Speed describes only how fast something is moving.• Velocity—includes the speed of an object AND the direction of its motion

Change in Velocity•Velocity can change in 2 ways

1. Change in speed

2. Change in direction

Or Both• Ex: a race car has a constant speed of 100km/hr around an oval track.• Speed is constant, but velocity

changes

Flash Card

• On the front write:

•Average Speed

• On the back write:

• the total distance traveled divided by the total time of travel

Flash Card

• On the front write:

•Instantaneous Speed

• On the back write:

• the speed at a given point in time

Acceleration• Acceleration—the rate of change of velocity.• The change in velocity over time• acceleration = change in velocity

time

• When something speeds up, it has a positive acceleration

• When something slows down, it has a negative acceleration.

Breaking Acceleration Apart

• Change in velocity= vfinal –Vstart

• Acceleration= vfinal –Vstart

• Time

• Units= distance (meters, miles)/sec2

Acceleration Triangle

Changing Direction• Remember:• A change in velocity

can be either a change in speed or a change in direction.• Any time an object

changes direction, its velocity changes and it is accelerating.

Negative vs. Positive Acceleration

• An object speeds up if its acceleration is in the direction of its motion.

• An object slows down if its acceleration is opposite to the direction of its motion.

Velocity vs Time Graph

of Positive Acceleration

Flash Card

• On the front write:

•Slope of graph

• On the back write:

• D vs T graph=speed

• V vs T graph=acceleration • Steeper slope=more

speed or acceleration

Velocity vs Time Graph of Negative Acceleration

Zero Acceleration•When an object has a constant velocity, it has 0 acceleration.

An Object Changing Acceleration

• How Stuff Works: Roller Coaster & The Human Body

• See acceleration happening

Flash Card

• On the front write:

•Acceleration

• On the back write:

• The change in velocity over time (draw triangle)

Flash Card

• On the front write:

•Velocity

• On the back write:

• The speed and direction of an object