Standard 8.1 The velocity of an object is the rate of change of its position

Anticipatory Set How does a flying Bird know it is moving? It sees objects on the ground that it passes When watching a football game, how do you know the distance of a pass? You see it move past the field markers If you were on a cruise ship how can you tell the boat is moving forward? You can look for coastal land, or by the stars in the sky

Standard 8.1 (a-c) A. Know that position is defined in relation to some choice of standard reference point and a set of reference directions. B. Students know that average speed is the total distance traveled divided by the total time elapsed and that the speed of an object along the path traveled can vary. C. Students know how to solve problems involving distance, time, and average speed.

LANGUAGE OF THE DISCIPLINE Position: Position: an objects place or location relative to a reference point Reference point: Reference point: a marker that is used to determine if something is in motion Motion: Motion: the change in an objects position relative to a reference point Speed: Speed: the measure of how far something moved in a given period of time Average speed: Average speed: how fast something moves over a given period of time

Motion An object is in motion if it changes position relative to a reference point. To see if in motion: – Pick a STATIONARY reference point – Indicate your position by + or – Left/right Up/down Front/behind

Position How can you describe the position? You use a reference Point to establish position. Position is when something is stationary

Relative Motion Relative motion – depending on what your reference point it things may or may not “be in motion” (see plane, skydivers, and ground)

Motion Example You and your classmate are riding the bus to school. Your classmate is 5 rows ahead of you. You look at the window and see a tree move past. You look across the aisle and see the seats are not moving. Is the bus moving? – yes Are you moving inside the bus? – no Is your classmate moving faster than you (since they are sitting further up)? – No, neither of you are moving inside the bus

Distance vs. Displacement Distance is the total length of the actual path between two points (yellow path) Displacement is the length and direction of a STRAIGHT line between the starting and ending points (red line)

SPEED Speed is also known as RATE Speed Equation Average Speed – Most objects vary in speed as they move, so we need to find the average speed – Equation:

Calculating Speed If a distance runner runs 10 miles in one hour, what is her speed. Speed = Distance Time Speed = 10 miles = 10 mph (miles per hour) 1 hour

Calculating AVERAGE Speed A cyclist travels 20 kilometers during the first 2 hours. Then he travels 16 kilometers during the next hour. What is his average speed? Average Speed = Total Distance Total Time v= 20 km + 16km = 36 km 2 h + 1 h = 3 h v= 12 km/h

Calculating Speed A skateboard rolls down a ramp at constant speed of 12 m/s. How many meters will the board travel in 4 seconds? Speed = 12 meters 1 second X 4 seconds Distance after 4 seconds= 48 Meters

Graphing Speed What is happening to the speed/ motion at the blue arrow?

Check for Understanding What do you need to determine if something is in motion? – A reference point What is the speed equation?

Practice & HW Guided Practice: – Read through Guided instruction on page and highlight important information – Complete the Guided questions in Measuring up on page – Raise hand for a stamp Independent Practice: – Complete questions 1-4 on page 24 HW: – complete questions 1-3 on page 25.

How can we make this balloon move along the string?

Standard 8.1 (d-e) D:Students know the velocity of an object must be described by specifying both the direction and the speed of the object. E:Students know changes in velocity may be due to changes in speed, direction, or both.

LANGUAGE OF THE DISCIPLINE Velocity: Velocity: speed and direction of an object Vector Quantity: Vector Quantity: a scientific quantity that contains a magnitude and direction Acceleration: Acceleration: the rate at which velocity changes over time Deceleration: Deceleration: negative acceleration, slowing down

velocity Remember it is: SPEED + DIRECTION – Example: the car is going 35 mph southeast Changes in velocity may be due to changes in SPEED, DIRECTION, or BOTH.

velocity Remember it is: SPEED + DIRECTION WHAT KIND OF JOBS WOULD KNOWING VELOCITY BE IMPORTANT? – Air Traffic Controller If something is moving at a constant speed around a track is it changing velocity? – Yes, because it is changing direction

acceleration does not just mean “speed up” In science, acceleration refers to increasing speed, decreasing speed, or changing direction. Sometimes we call decreasing speed, DECELERATION

Calculate acceleration Acceleration= Final Velocity - Initial Velocity Time

Practice Problem Algernon was running a maze. He must run 20 cm forward, 10 cm to the left, and 30 cm forward. Algernon moves at about 90 cm per minute. How many seconds will it take for him to complete course? Add up total distance: = 60 cm Set up problem 60 cm = 90 cm X 60 secs (1 min) Cross multiply to solve for X – 60 (60) = 90 X – 3600/ 90= 40 – X= 40 seconds

Check for Understanding Do the following scenarios represent speed and/or acceleration? MotionSpeed?Velocity? A car completes one lap at a car races at 185 mph Geese flying south at 25 mph Students leaving school at 3:45 A baseball travels at an angle of 45 degrees southwest at 65 mph

Practice & HW Guided Practice: – Read through Guided instruction on page and highlight important information – Complete the Guided questions in Measuring up on page – Raise hand for a stamp Independent Practice: – Complete questions 1-4 on page 28 HW: – complete questions 1-3 on page 29 (and anything else not finished).

Anticipatory Set With your arms: What direction does the Y-axis go? What direction does the X-axis go?

Standard 8.1 (f) F. Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction.

LANGUAGE OF THE DISCIPLINE Slope: Slope: in a linear function it shows the rate of change (such as speed or position) over time Linear: Linear: changes over time by a constant amount Nonlinear: Nonlinear: changes over time by differing amounts Origin: Origin: (0,0), where the x-axis and y-axis meet Zero point: Zero point: where the value of Y equals 0

Graphing Time is always on the x-axis It is “independent” of the speed or distance Speed or distance is always on the y-axis It is “dependent” on the time

Position Graph Shows an object’s position over time Graph: – Y axis: distance – X axis: time What can you tell What can you tell about the position about the position By the graph?

Types of Lines (insert picture)

Zero Points Zero Points: when Y value is 0 on a position graph All movement away from starting point is (+) and all movement coming back is (-)

Zero Points Zero points are relative to what you set as the base location/position Example: You might track a basketball players position on the court. You set their basket as zero position OR… you might set zero point as half court line

Speed Graph Used to show changes in speed over time – A flat line does not indicate NO movement- it indicates CONSTANT movement What can you tell me What can you tell me about the speed of about the speed of this bus?

Check for Understanding What is happening in this graph

Practice & HW Guided Practice: – Complete Practice Worksheet Raise hand for a stamp Independent Practice: – Read through Guided instruction on page and highlight important information – Complete the Guided questions in Measuring up on page HW: – complete questions on page 34 and 35 (and anything else not finished).