Motion Speed velocity and acceleration LESSON Speed and

Motion Speed, velocity and acceleration

LESSON Speed and Velocity Essential Questions • What is speed? • What are ways velocity can change? • How do speed and velocity differ?

LESSON Speed and Velocity Vocabulary Watch out for these words! • speed • constant speed • instantaneous speed • average speed • velocity

LESSON Speed and Velocity Inquiry How Fast? When you hear the word cheetah, you might think of how fast a cheetah can run. As the fastest land animal on Earth, it can reach a speed of 30 m/s for a short period of time. Other than how fast it runs, how might you describe the motion of a cheetah?

How motion is described � Position: the location of an object � Motion: a change in an object's position using a reference point. � An object is in motion if it’s distance from a reference point is changing � escalator � Reference point: a place or object that is used to determine another's location. � Used to make the description clear �Ex: I sit 3 seats to the right of the door

How is speed described? � Speed: the measure of how quickly distance changes with time (How fast the object goes in a certain amount of time) � Unit of measurement: m/s � Average speed: average speed an object goes including the times speed increased and decreased. � Instantaneous speed: speed of an object at a specific moment in time � Can be different from average speed.

PRACTICE What is Francisco’s reference point? ? ? Is Francisco in motion?

How is velocity described? � Velocity: speed and direction of a moving object � Represent velocity: arrows � Length indicates speed �Longer = greater speed � Direction �Pointing showing motion or path

Velocity calculations & changes in velocity � Formula: � The velocity of the ball is changing continually because both the speed and direction of the ball changes as it bounces. � The changes in the arrows mean that the velocity is constantly changing.

Vectors: � Vector: something that has both size and direction � I'm applying for a villain loan. I go by the name of Vector. It's a mathematical term, represented by an arrow with both direction and magnitude. Vector! That's me, because I commit crimes with both direction and magnitude. Oh yeah!

PRACTICE What is the formula for speed? What is the formula for velocity?

LESSON Speed and Velocity Solve for Average Speed Melissa shot a model rocket 360 m into the air. It took the rocket 4 s to fly that far. What was the average speed of the rocket?

LESSON Speed and Velocity Solve for Average Speed, continued STEP 1 This is what you know: distance: d = 360 m STEP 2 STEP 3 and time: t = 4 s

LESSON Speed and Velocity Solve for Average Speed, continued Step 4

How is acceleration described? � Acceleration is a measure of how quickly velocity changes � Occurs when there is a change is speed, change is direction or both

Acceleration and Velocity � Acceleration is a change in velocity � When velocity is not changing, acceleration is 0. � Ex: a car driving down a hill at a constant speed and direction (constant velocity), has no acceleration.

Time distance graphs � Compare distance an object travels to the time it takes to get there. � Represented on graph: � Speeding up � Slowing down � Staying still – no motion

Steps to find average speed on graph

LESSON Speed and Velocity

LESSON 4. 1 Speed and Velocity