1. Movement depends on your point of view
Chapter 1: Motion Section 1: Describing and Measuring Motion How do you recognize motion?
An object is in motion when its distance from another object is changing
Movement depends on your point of view

2. What is a reference point?
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 reference point

3. What is the basic unit of length?
The meter – a little longer than a yard

4. A millimeter – There are 1,000 millimeters in a meter
What do scientists use to measure the length of an object smaller than a yard?
A centimeter – one hundredth of a meter, so there are 100 centimeters in a meter
A millimeter – There are 1,000 millimeters in a meter

5. How do scientists measure long distances?
The kilometer – There are 1,000 meters in a kilometer

6. How do scientists calculate speed?
Speed – the distance the object travels in one unit of time
Rate – tells you the amount of something that occurs or changes in one unit of time
Speed = distance
time

7. What is constant speed?
If the speed of an object does not change, the object is traveling at a constant speed

8. What is average speed?
Most objects do not move at constant speeds for very long
To find average speed divide the total distance by the total time
Car trip

9. What is Velocity? Speed in a given direction
When you know the speed and direction of an object’s motion, you know the velocity of the object
Example 15 km/hour westward

10. How do you graph motion?
You can show the motion of an object on a line graph in which you plot distance against time
Time is along the x-axis and distance on the y-axis

11. How do you interpret motion graphs?
A straight line indicates a constant speed
The steepness depends on how quickly or slowly the object is moving
The faster the motion the steeper the slope

12. Section 2: Slow motion on Planet Earth
According to their explanation, known as the theory of plate tectonics, Earth’s plates move ever so slowly in various directions

13. How fast do plates move?
Some small plates can move as much as several centimeters per year, whereas other move only a few millimeters per year

14. How can you calculate the distance an object has moved?
Rearrange the speed formula
Distance = Speed x Time
Converting units – choose a conversion factor that will allow you to cancel units

15. Section 3: Acceleration What is Acceleration?
The rate at which velocity changes
In science, acceleration refers to:
increasing speed
decreasing speed
changing direction

16. How do you calculate acceleration?
To determine the acceleration rate of an object, you must calculate the change in velocity during each unit of time
Acceleration = Final velocity – Initial velocity
Time

17. How do you interpret graphs to determine acceleration?
Acceleration vs. Constant speed
The acceleration at any moment is equal to the slope of the velocity time graph at that moment in time

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