One Dimensional Motion Unit 1 One Dimensional Motion

What does the speedometer in my car REALLY measure? Essential Question 1 What does the speedometer in my car REALLY measure?

Is the person in this picture moving?

Defining Motion Reference Point: An object that looks motionless to an observer. Motion: When an object moves closer or farther away from a reference point.

See how reference points work?

Space and Time Physics looks at the world through an objects movement through SPACE and through TIME.

Position Position: The physical location of an object in a frame of reference.

Describing Motion

Using Math to describe motion The position and time of an object can be written down in a table or can be put on a scatter plot or line graph.

Using Math to describe motion Position (m) Time (s) 2 9 5 14 10 20

Physics Vocabulary Things you’ll hear the teacher say . . . Magnitude: The size of the quantity measured. Always positive. Example: Mr. White’s weight has a magnitude of 180 lbs.

Crazy Physics Vocabulary Things you’ll hear the teacher say . . . Scalar Measurement: Measureable quantity that just has a magnitude. Mr. White’s weight is a scalar measurement.

Crazy Physics Vocabulary Things you’ll hear the teacher say . . . Vector Measurement: A measurable quantity that must also have a direction stated. Represented by arrows.

Vector Example

Sounding Smart With Science Physics uses the term Velocity to describe how quickly something is moving. Velocity is as vector quantity. Velocity: Speed with a direction.

Velocity Directions with Velocity Normally going to the right or up is considered the positive directions.

Speed vs. Velocity Speed: The distance something travels in a given amount of time. How fast something is moving. How are speed and velocity different?

Average vs. Instantaneous Velocity Instantaneous Speed: The velocity at any given instant in time (like the reading on a speedometer in a car)

Average vs. Instantaneous Speed Average Speed: The average of ALL the instantaneous speeds (Total Distance ÷ Time of Travel)

Relative Motion The same motion can be seen differently depending on where the observer is standing.

Adding Velocity Resultant Velocity: Observed motion when velocities combine. Velocities in the same direction ADD. Velocities in OPPOSITE directions SUBTRACT.

Relative Velocity A man on a river bank is watching a fishing boat go up a river. The speedometer on the boat reads 25 mph and the river current is flowing at 4 mph. How fast does the boat appear to be moving to the man on the bank?

Average Velocity Equation 𝑣= 𝑑 𝑡 Symbol Name Unit v Average velocity Distance Unit/ Time Unit & Direction d Distance Distance Unit t Elapsed Time Time Unit

Speed and velocity Practice Problem Set Example 1 The bearded dragon is the fastest reptile on the planet. It can cover 55 meters in just 5 seconds when it is running at top speed. What is the average top speed of the bearded dragon?

Speed and velocity Practice Problem Set Example 1 The slowest animal ever discovered was a crab found in the Red Sea. It traveled with an average speed of 5.7 km/year. How long would it take to travel the length of a football field (109.1 meters)? Record your answer in DAYS!

Speed and velocity Practice Problem Set Example 3 Mr. White is driving his car from east to west across the parking lot. If it takes his vehicle 30 seconds to travel 45 meters, what is the average velocity of his car?

Does acceleration mean going faster? Essential Question 2 Does acceleration mean going faster?

Acceleration: The rate at which velocity changes.

Acceleration in common Terms Ways velocity changes. Speed up (Velocity Increases) Slow Down (Velocity Decreases) Turn (Change Direction)

Acceleration and Direction Speeding up: Anytime the Velocity & Acceleration Vectors point in the same direction. Slowing down: Anytime the Velocity & Acceleration Vectors point in the opposite direction.

Acceleration Equation Symbol Name Unit a Acceleration Distance Unit / Time Unit 2 ∆v Change in Velocity Distance Unit / Time Unit v End Velocity v0 Start Velocity t Time of Acceleration Time Unit

Distance & Acceleration Range (Distance) Equation for a constant acceleration. 𝑑= 𝑎∙ 𝑡 2 2 * This equation only works with objects starting or ending at REST!

Acceleration Practice Problem Set Example 1: Grace is driving her sports car at 30 m/s when a ball rolls out into the street in front of her. Grace slams on the brakes and comes to a stop in 3.0 seconds. What was the acceleration of Grace’s car?

Acceleration Practice Problem Set Example 2: While driving a car a down a four-lane highway, Eddie comes up behind a slow-moving truck and decides to pass it in the left hand lane. If Eddie can accelerate at 5.00 m/s2, how long will it take him to increase his car’s velocity by 10 m/s?

Acceleration Practice Problem Set Example 3: A driver spots a red light up ahead and applies the brakes to make the car slow at a rate of 4 m/s2. If the car travels 18.0 meters while the driver presses the brake pedal, how long did they apply the brakes?

Essential question 3 How can the graphing I learned in Algebra help me understand how real things move?

Position vs. Time Graphs Graphs can show how something moves in a single dimension over time. Moving Man

Position vs. Time Graph

Position vs. Time Graphs Describe the motion in each graph? t D t D t D

Position vs. Time Graphs What does the slope of a Position vs. Time graph mathematically represent?

Position vs. Time Graphs Using Graphs to find Instantaneous and Average Velocity

Velocity vs. Time Graphs Graphs can also show how fast something is moving over time.

Velocity vs. Time Graphs How would you describe the motion in each of the graphs below? t v t v t v

Velocity vs. Time Graphs What does the slope of velocity vs time graphs mathematically represent?

Making a Graph from Another Graph Graphing Motion Notes Handout