Warm up problem…

If you walked 20 meters in 5 seconds what was your rate of speed?

Hints– Take the distance and divide by the time– Answer will be in Meters per Second (m/s)

MotionAn object is moving

when its distance from another object is changing.

Frame of Reference:

A place or object used for comparison to determine if something is in motion.

An object is in motion if it changes position relative to a frame of reference or reference point.

Distance

Describes how far something has moved.

Measurement must include units

m meter

cm centimeter

km kilometer

mi. miles, ft. feet,

Displacement: The distance moved from the starting point. (also must include the unit of measurement)

Displacement and distance

3 successive plays in a football game

(+)5 yard run

(+)10 yard pass

(-) Tackle for 6 yard loss.

What is the distance?

What is the displacement?

Data Table

Create a table to hold the following information:

Time (Min and Seconds)

Distance (m)

Time

Min (sec)

Distance

(m)

0 (0)

1 (60)

2 (120)

3 (180)

4 (240)

5 (300)

6 (360)

7 (420)

8 (480)

Track instructions

Begin together Listen for time, and record your TOTAL

progress each minute. During the 3rd minute of the you must

travel significantly faster than previously.

During the 6th minute you must stop completely.

1 lap = ______ m

Create a line graph.

Y-axis: distance (m) X-axis: Time (seconds) Plot the cumulative distance for each minute. Calculate your average speed for the entire 8

minutes Circle your fastest minute and calculate the

speed during that minute. Do your calculations in the margin of the

graph

On the back of the graph paper…

Describe the activity Describe what you notice about the slope of

the graph during your slowest and fastest minutes.

EXTENSION Collect data from 2 other people and find

– the average distance traveled at each minute (data point),

– record the data into a data table (make new column labeled group average),

– add this information to your graph

Calculating average speed

Ave. Speed = total Distance

total Time

Solve this problem: Find the speed of runner who sprints 400 meters in 80 seconds.

Show your work and include labels for each number

Calculating Speed An elevator operates at an average

speed of 8 m/s. If the 60th floor is 219m above the 1st floor, how long does it take the elevator to go from the first floor to the 60th floor.

s=d=t=

Calculating SpeedA motorcyclist travels an average speed

of 20 km/hr. If the cyclist is traveling to the beach 5 km away. How long does it take the cyclist to make the trip?

s=

d=

t=

Average speed: total distance/total time

Instantaneous speed: the speed at a specific time (like your car speedometer)

Graphing Motion

Distance v. Time Graph

Distance is on the y-axis

Time is on the x-axis

The slope is the instantaneous speed.

Warm UP

Find the average speed:

You run 100 m in 15 seconds, walk 100m in 50 seconds, and then jog 200m in 40 more seconds.

Average speed and Instantaneous Speed

Describe a bike ride from Whittell to Kahle community center.

Share/Compare with your neighbor.

Using a whiteboard, create a speed v. time graph of your bike ride.

1. What was the average speed of Dominick?

2. What was the total distance traveled by Skylar?

3. What was Skylar’s average speed?

distance

mtime (minutes)

distance skated

Speed and Velocity

Velocity is just like speed, but with more information.

Velocity tells you how fast (speed) and which direction.

VELOCITY is speed in a given direction.

Motion of the earth Motion can be so slow we cannot see it. For really slow things the units must be

adjusted. ( meters / second )

object possible units

slug

flower growing

earth tectonic plate

Chapter 1 MotionSection 2 Acceleration

Acceleration The rate at which velocity changes.

[Velocity = Speed, Direction]

Acceleration can be:

1. Increasing Speed

2. Decreasing Speed

3. Changing Direction

Acceleration= Final Velocity – Initial Velocity

TIME The coaster is

moving 4m/s at the top of the ride.

3 seconds later, at the bottom it is moving 22m/s.

What is the coasters acceleration?

The coaster is moving 4m/s at the top of the ride.

3 seconds later, at the bottom it is moving 22m/s.

What is the coasters acceleration?

a=

Vi=

Vf=

t=

Acceleration=Vf – Vi t

Solve

Robbie is cruising down Olympic ski run (Heavenly) at 4m/s. He plans to pull a rodeo on the next table so he speeds up to 12 m/s. This takes 4s.

Determine Robbie’s acceleration.

Show your work. Acceleration formula is on PG 48

Warm Up: Acceleration Marshall is running

lines during basketball practice.

He is running at 5 m/s during the drill.

During the last 2 seconds He eases up to 1 m/s.

What was Marshall’s acceleration at the finish of the drill?

Graphing Acceleration

Where is the object increasing velocity?

Where does the object have constant velocity?

Where does the object have negative acceleration? (slow down)

Graphing Acceleration: Meaning of the slope

Speed v. Time

pos = acceleration

(speeding up)

0 =

constant speed

neg =

-acceleration (slowing down)

Calculate acceleration

A rocket’s speed is 10000 m/s as it reenters earth’s atmosphere. 30 seconds later the rocket is moving at 5000 m/s. Calculate the acceleration.

Create a speed vs. time graph for the following

Kyle is riding up the stagecoach.

At the top of the hill, he gets off & stops to buckle in.

He then starts going down stagecoach continuously gaining speed…

until he has an epic crash and comes to a complete stop.

Creating an acceleration problem1. Pick an object that is moving (or is able

to move)2. What is its initial velocity? (m/s)3. What is its final velocity? (m/s)4. How long did this velocity change take?

(elapsed time in seconds)5. Final question of problem: What is the

acceleration?Put the elements above into a word

problem.

Force

A push or a pull on an object.

An unbalanced force will accelerate an object.

A balanced force will allow an object to maintain constant velocity.

Inertia

An object at rest will stay at rest unless acted upon by a force.

Newton’s First Law of Motion:

INERTIA

Data Table

Angle Trial # Time (s) Average time (s)

Average Speed(m/s)

1

2

3

1

2

3

1

2

3

1

2

3

Positive Slope

On a distance v. time graph what does a positive slope mean?

On a velocity v. time graph what does a positive slope mean?