1. Speed, Velocity and Acceleration
Motion

2. Distance & Displacement

3. Must have a frame of reference
Motion: a change in position relative to a frame of reference
Frame of Reference: The object or point from which movement is determined.
A system of object that are not moving with respect to one another.
Must have a frame of reference
to determine motion.

4. Choosing a Frame of Reference
Relative Motion: movement in relation to a frame of reference.
Most common frame of reference is Earth.
Choose a frame of reference that allows you to more accurately describe motion.

5. Distance Distance: The length of a path between two points
SI unit: meter (m)
Can use kilometer (km) or centimeter (cm)

6. Displacement
Displacement: the direction from the starting point and the length of a straight line from the starting point to the ending point
Includes distance and direction
Example of a vector (has both magnitude & direction)
Example:
Distance: the girl walked 5 blocks
Displacement: the girl walked 5 blocks east

7. Combining Displacements
Add displacements using Vector addition
Straight line
If 2 displacements are in the same direction-add vectors
If 2 displacements are in the opposite direction-subtract vectors
Not straight line
Need to combine by graphing…creating a Resultant vector

8. Speed & Velocity

9. Speed
Speed: the ratio of the distance an object moves to the amount of time the object moves
Speed = Distance or s = d
Time t
SI unit: meter/second (m/s)

10. Types of Speed
Average Speed: the total distance traveled divided by the time it takes to travel that distance
Ex. Average speed over an entire trip
Instantaneous speed: the rate at which an object is moving at a given moment in time
Ex. Speed at a given moment

11. Graphing Constant Speed
Speed = Slope of the line

12. Graphing Varying Speed
Speed is changing...so, slope for each section is the speed for that time

13. Velocity Velocity: description of both speed and direction of motion
Velocity is a vector (can be added like vectors)
Velocity = displacement or v = d
time t
SI unit: m/s

14. Acceleration

15. Acceleration Acceleration: rate at which velocity changes
Change in speed, direction or both
Deceleration: negative acceleration
an object slows down
Constant acceleration: a steady change in velocity

16. Change in Speed Occurs when an object speeds up or slows down
Direction is constant
Ex. Free fall: the movement of an object toward Earth due to gravity

17. Change in Direction Occurs when an object changes direction
Speed is constant
Ex. Riding a carousel
Ex. Riding a Ferris wheel

18. Change in Speed & Direction
Occurs when there is a change in both speed and direction
Ex. Riding a roller coaster

19. Calculating Acceleration
Change in velocity divided by the total time
Acceleration = (vf – vi) t
vf: final velocity
vi: initial velocity
SI unit: m/s2

20. Graphing Acceleration
Acceleration = slope of the line