1. https://youtu.be/Bpid0LBTqWg
Unit 7 Matter in Motion

2. Objective unit 7
Describe the motion of an object by the position of the object in relation to a reference point.
Identify the two factors that determine speed.
Explain the difference between speed and velocity
Analyze the relationship between velocity and acceleration.
Demonstrate that changes in motion can be measured and represented on a graph.

3. I. Measuring Motion A. Observing Motion by Using a Reference Point
Motion is an object’s change in position relative to another object, or reference point.
The object that appears to stay in place is called a reference point.
The direction of an object’s motion can be described with a reference direction;
north
South
East
west Up
down

4. Common Reference Points: The Earths surface is a common reference point for determining motion
Trees, buildings, non-moving objects

5. B. Speed depends on distance and time
Speed= distance traveled by an object divided by the time taken to travel that distance
SI unit for speed= m/s
Other common units= km/h, ft/s, mi/h
To determine the average speed=
Average speed= total distance
total time
Actual distance varies from estimated difference b/c the actual is not constant due to weather, traffic, etc…

6. Complete in your notes

7. C. Velocity : Direction Matters
Velocity = speed of an object in a particular direction
Speed and velocity DO NOT have the same meaning
Velocity looks at direction
Speed= 55mi/h but velocity would be 70mi/h north
An objects velocity changes if its speed OR direction changes
The car can change velocity by going from 55mi/h to 70 mi/h OR by changing directions to East when going around a curve

8. Resultant velocity= combing two velocities
Combing 2 velocities in the SAME direction= add them together
Combing 2 velocities in different direction= subtract the velocities

9. D. Acceleration https://youtu. be/I3GlErUi2q0
Acceleration= rate at which velocity changes
Acceleration occurs if speed changes, direction changes, or both
Positive acceleration: increase in velocity
Negative acceleration (deceleration): decrease in velocity
Faster the velocity changes the greater acceleration is
Expressed as meters per second per second (m/s/s) or m/s2
Can be graphed as velocity (y axis) vs time (x axis)

10. 7. Calculating Average Acceleration
Average acceleration= final velocity-starting value
time it takes to change velocity
Plane passes over point A at a velocity of 240m/s north. 40 seconds later it passes over point B at a velocity of 260m/s north. What is its average velocity?

11. Graphing acceleration
Time in second (s)