Position and MotionPosition and Motion

What is motion?What is motion?Motion is when an Motion is when an object changes object changes position.position.

How do you know How do you know that the racecar that the racecar moved?moved?– It changed its It changed its

position on the position on the track.track.

How can you tell something has How can you tell something has changed position?changed position?

In order to see if In order to see if something has something has changed position changed position (motion) you need a (motion) you need a reference point.reference point.– For example, the For example, the

starting or finishing starting or finishing line of a racetrack. line of a racetrack.

What is distance?What is distance?

Easy question!Easy question!

Distance is how far an object has Distance is how far an object has moved.moved.

We measure distance in METERS!We measure distance in METERS!

What is displacement?What is displacement?

Suppose a runner jogs north to the Suppose a runner jogs north to the 50-m mark and then turns around 50-m mark and then turns around and runs back south 30-m. and runs back south 30-m.

Total distance is 80-m.Total distance is 80-m.

Two directions - north and south.Two directions - north and south.

Displacement is the distance and Displacement is the distance and direction.direction.

What is the difference between What is the difference between distance and displacement?distance and displacement?

Distance is how far Distance is how far something has something has moved.moved.

Displacement is Displacement is how far something how far something has moved AND has moved AND the direction it the direction it moved!moved!

What is speed?What is speed?

Speed is the distance an object Speed is the distance an object travels over time.travels over time.

Any change over time is called a Any change over time is called a RATE.RATE.

Speed is the rate at which distance is Speed is the rate at which distance is traveled.traveled.

SPEED FORMULASPEED FORMULASpeed = Distance / TimeSpeed = Distance / Time

S = D / TS = D / T

Speed ExampleSpeed ExampleSuppose you ran 2 km in 10 Suppose you ran 2 km in 10 min.min.– What is your rate?What is your rate?

S = D/T S = D/T

S= 2 km /10 min.S= 2 km /10 min.

S= 0.2 km/min.S= 0.2 km/min.

Remember the units!!!Remember the units!!!

Constant Speed…Constant Speed…

What does constant mean?What does constant mean?

If you are driving on the highway and If you are driving on the highway and you set your cruise control, you are you set your cruise control, you are driving at a constant speed.driving at a constant speed.

What would a constant speed graph What would a constant speed graph look like?look like?

Constant Speed GraphConstant Speed Graph

Do you always go the same speed?Do you always go the same speed?

No! Most of the No! Most of the time you are time you are increasing speed, increasing speed, decreasing speed, decreasing speed, or stopping or stopping completely!completely!

Think about driving Think about driving a car or riding a a car or riding a bike!bike!

What would a changing speed What would a changing speed graph look like?graph look like?

What is average speed?What is average speed?

How do you find an average?How do you find an average?

Average speed is the total distance Average speed is the total distance traveled over the total timetraveled over the total time

Avg. Speed = Total D / Total TAvg. Speed = Total D / Total T

What is Instantaneous speed?What is Instantaneous speed?What does a speedometer in a car do?What does a speedometer in a car do?– It shows how fast a car is going at one It shows how fast a car is going at one

point in time or at one instant.point in time or at one instant.

Instantaneous speed is the speed at a Instantaneous speed is the speed at a given point in time. given point in time.

What is Velocity?What is Velocity?

SpeedSpeed is how fast something is is how fast something is moving.moving.

VelocityVelocity is how fast something is is how fast something is moving and in what direction it is moving and in what direction it is moving.moving.

Why is this important?Why is this important?– HurricanesHurricanes– AirplanesAirplanes

Speed or Velocity?Speed or Velocity?If a car is going If a car is going around a racetrack, around a racetrack, its its speedspeed may be may be constant (the constant (the same), but its same), but its velocityvelocity is is changing because changing because it is changing it is changing direction.direction.

Speed or Velocity?Speed or Velocity?Escalators have the Escalators have the same speed same speed (constant), but (constant), but have different have different velocities because velocities because they are going in they are going in different directions.different directions.

Is it moving?Is it moving?Is the earth moving right now?Is the earth moving right now?– How do you know?How do you know?

How did the countries get where they are How did the countries get where they are today?today?– How do you know?How do you know?

Is it still moving?Is it still moving?

Are continents still Are continents still moving?moving?– How do you know?How do you know?