1. Speed, Velocity, Acceleration

2. Motion
Nothing in the universe stays still. A book on a table appears to be sitting still, but Earth is moving in its orbit around the sun at a speed of 66,000 miles per hour. You and the book move with Earth.
Change in position during a time period
3 types of motion
Speed
Velocity
Acceleration
The motion of objects can be described by wordsgoing fast, stopped, slowing down, speeding up, and turning. These words are associated with mathematical quantities that have strict definitions and are used to describe the motion of objects.
Scalars are quantities that are fully described by a magnitude (or numerical value) alone.
Vectors are quantities that are fully described by both a magnitude and a direction

3. Distance and Displacement
Distance and displacement are two quantities that may seem to mean the same thing yet have different definitions and meanings.
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion.
Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
A physics teacher walks 4 meters East and 2 meters South
-total distance=6 meters
- displacement= 4.47 meters; SE

4. Speed 1. Definition: Rate at which an object moves
Consider a bicycle moving along the road. To understand the concept of speed, think about the following two questions. • How many meters does the bicycle move in each second? • Does the bicycle move the same number of meters every second?
Speed
1. Definition: Rate at which an object moves
2. Formula: Distance divided by time (s=d/t)
3. Units: m/s or km/sspeed will always have 2 units (1 for distance traveled; 1 for time)
Speed the distance an object travels in a certain amount of time.
the bicycle is moving 1 meter every second (1m/s).
 The bicycle is moving 3 meters every second (3m/s).

5. Units for speed
“per” “for every” or “for each” or “divided bya speed of 100 kilometers per hour100 kilometers for each hour.“per”
Speed is a ratio of distance (distance units) over time (time units)
In the metric system, distance is measured in centimeters, meters, or kilometers. If distance is in kilometers and time in hours, then speed is expressed in kilometers per hour (km/h). Other metric units for speed are centimeters per second (cm/sec) and meters per second (m/sec). Speed is also commonly expressed in miles per hour (mph).
Distance
Time
Speed
Abbreviation
Centimeters (cm)
Seconds (s)
Centimeters per second
Cm/s
Meters (m)
Second (s)
Meters per second
m/s
Kilometers (km)
Hours (hr)
Kilometers per hour
Km/hr
Miles (mi)
Miles per hour
Mi/hr

6. Average Speed vs. Instantaneous Speed
Both bicycles in the previous diagram are moving at constant speedmeans the same distance is t traveled every second.
Instantaneous speed the speed at any given moment in time
Average speedthe average of all instantaneous speeds; found simply by a distance/time ratio

7. Calculating Speed
Speed the distance traveled in a given amount of time.
to calculate the speed of an object, you need to know two things:
1.) The distance traveled by the object.
2.) The time it took to travel the distance.
Example: What is your speed if you drive 150 kilometers in 1.5 hours?
What do you know:
d= 150km
t=1.5hrs d s t

8. Calculating Speed Practice
1.) A bicyclist, traveling at 22 miles per hour, rides a total of 44 miles. How much time (in hours) did it take? 2.) A mouse is moving in a straight line at a steady speed of 2 m/sec for 10 seconds. How far (in meters) did the mouse travel? 3.) The gray wolf is a threatened animal that is native to the United States. A wildlife biologist tracks a gray wolf that moves 250 meters in 100 seconds. Calculate the wolf’s speed in meters per second. 4.) It takes Brooke 10 minutes to run 1 mile. What is her speed in miles per minute?

9. More Calculating Speed Practice
1.) A bicyclist, traveling at 34 miles per hour, rides a total of 78 miles. How much time (in hours) did it take?
2.) A mouse is moving in a straight line at a steady speed of 1.5 m/sec for 20 seconds. How far (in meters) did the mouse travel?
3.) The gray wolf is a threatened animal that is native to the United States. A wildlife biologist tracks a gray wolf that moves 560 meters in 250 seconds. Calculate the wolf’s speed in meters per second.
4.) It takes Brooke 30 minutes to run 5 mile. What is her speed in miles per minute?

10. t d V 1. Definition: Describes speed plus direction (n, s, e, w)
Velocity
1. Definition: Describes speed plus direction (n, s, e, w)
2. Formula: D/T plus direction (same formula for speed)
3. Units: m/s or km/s, north, south, east or west

11. Calculating Velocity Practice
1.) If a runner is running east at 10 m/s, what is her velocity?
2.) If you’re rowing a boat downstream at 16 km/hr, and the current is moving upstream at 10 km/hr. How fast does the boat “look” like it’s going to someone on shore (velocity)?
3.) If you’re rowing a boat upstream at 15 km/hr, against a current moving at 8 km/hr. What is you’re actual velocity to an observer on the shore?

12. Acceleration
V2=final velocity
V1=initial velocity
T=time
1. Definition: Rate of change in velocity (how fast you are getting faster/slowing down)
Speeding up, slowing down, changing direction
2. Units: m/s/s or km/s/sacceleration always has three units
- Increasing velocity - positive acceleration
- Decreasing velocity - negative acceleration- deceleration

13. Acceleration Calculate the acceleration of the boat.
As you go down the hill, your speed gets
faster and faster—you accelerate. Your acceleration depends on the steepness of the hill
Calculate the acceleration of the boat.
Calculate the acceleration of the car.

14. Calculating Acceleration Practice
1.) A roller coaster’s velocity at the top of a hill is 10m/s. Two sec later it reaches the bottom of the hill with a velocity of 26 m/s. What is the acceleration of the roller coaster?
2.) A roller coaster’s velocity at the bottom of a hill is 25 m/s. Three seconds later it reaches the top of the next hill, moving at 10 m/s. What is the deceleration of the roller coaster?
3.) A car is traveling at 60 km/hr. It accelerates to 85 km/hr in 5 seconds. What is the acceleration of the car?

15. -Acceleration has 3 variables (initial velocity, final velocity, and time)  it will also have 3 units
-Variations on the primary acceleration formula can solve for any one of the variables
t=V2-V1 V1=V2-at a
V2=at + V1

16. Calculating Acceleration Practice contin…
1.) A skater increases her velocity from 2.0 m/s North to 10.0 m/s North in 3.0 seconds. What is the skater’s acceleration? 2.) A car accelerates at a rate of 3.0 m/s2. If its original speed is 8.0m/s, how many seconds will it take the car to reach a final speed of 25.0 m/s? 3.) Lucas’ brand new Chevrolet Camaro accelerates at a rate of m/s2. If it takes him 6 seconds to accelerate to 160 m/s, what was his initial speed?