Objective: Don’t have a sheet at the end Vocabulary Tag 5 Minutes Objective: Don’t have a sheet at the end If you have a sheet read off a definition to a classmate If they guess an incorrect term give them the sheet If they guess correctly, move on to the next person

Speed, Velocity, and Acceleration

Speed The amount of distance traveled per unit of time. Speed= Distance Time

FRICTION Friction is a contact force that opposes motion, it causes heat, damage, wear and slowing  Friction can be reduced by… lubrication, streamlining (aerodynamics), slowing down, smoothing surfaces EXPT sliding on oil or sandpaper or bike stopping on dry, wet surface 4

Speed, Distance, Time Formulas

Formula Triangle

How to Use the Formula Triangle

Calculating Speed Given Distance & Time Divide Distance by Time Distance ÷ Time = Speed Speed = Distance ÷ Time

Practice: Angie ran 15 meters in 5 seconds. What was her speed? Speed = Distance Time Speed= 15 m 5 s S T Speed = 3 m/s

Practice: Angie ran 100 meters in 10 seconds. What was her speed? Speed = Distance Time Speed= 100 m 10 s S T Speed = 10 m/s

Calculating Distance Given Speed & Time Multiply Speed and Time Distance = Speed X Time Speed X Time = Distance

Practice: If a car is traveling at 20 m/s, how far will it travel in 60 seconds? D Distance = Speed X Time Distance = 20 m/s X 60 s S T Distance = 1,200 m

Practice: If a car is traveling at 100 m/s, how far will it travel in 60 seconds? D Distance = Speed X Time Distance = 100 m/s X 60 s S T Distance = 6,000 m

Calculating Time Given Distance and Speed Divide Distance by Time Distance ÷ Speed = Time Time = Distance ÷ Speed

Practice: A train traveled at a speed of 50 m/s. How long did it take the train to travel 3,000 m? D Time = Distance Speed Time = 3,000 m 50 m/s S T Time = 60 s

Practice: A train traveled at a speed of 100 m/s. How long did it take the train to travel 3,000 m? D Time = Distance Speed Time = 3,000 m 100 m/s S T Time = 30 s

Ticket Out the Door Put name and period on a scrap piece of paper, write answer, put paper in the appropriate folder as you leave. GREEN = I Know It YELLOW = I Sort of Know It Red = I Don’t Get it What is the speed of an object that goes 5 cm in 1 second How much time does it take for a person walking 1000cm/s to travel 5000 cm What distance does a person walk in 1 minute if they travel at 1 meter per second

Problems from Yesterday What is the speed of an object that goes 5 cm in 1 second

Problems from Yesterday 2. How much time does it take for a person walking 1000cm/s to travel 5000 cm

Problems from Yesterday 3. What distance does a person walk in 1 minute if they travel at 1 meter per second

Interpret The Graph Below:

FRICTION Friction is a contact force that opposes motion, it causes heat, damage, wear and slowing Usually the increase mass results in the increase of Friction Forces.  Friction can be reduced by… Lubrication streamlining (aerodynamics), slowing down, smoothing surfaces Example: sliding on oil or sandpaper or bike stopping on dry versus wet surface EXPT sliding on oil or sandpaper or bike stopping on dry, wet surface 22

Velocity Velocity is like speed, but it includes a change in position. Velocity is stated as speed and direction Example: The car was traveling at 60 miles per hour to the east.

Velocity (continued) Stand up and take 2 steps backwards. Now take 2 steps forward. Did you walk at a certain speed? Yes. You took a total of 4 steps over the span of a few seconds. Do you have velocity? No, because your position didn’t change. You ended at the same point you started at.

Acceleration Acceleration is the rate at which an object’s velocity changes. This includes Changing speed Changing direction

Acceleration Acceleration is the rate at which an object’s velocity changes. Acceleration Formula: Change in Velocity -------------------------- Change in time

Acceleration Example: 50m/s – 0m/s ------------------- = 5s – 0s 50 m/s 10m/s ---------- = ----------- or 10m/s/s 5s 1s Instructions for Calculating Acceleration: End Velocity – Start Velocity -------------------------------------- Ending Time – Starting Time

Answer These in Notes A sky diver jumps out of a plane and in 5.4 seconds falls 286.2 meters. What is the sky divers average speed? What was the sky divers average acceleration 3. Do you think this skydiver would continue to accelerate?

Motion Graphs

DISTANCE/TIME GRAPHS A car takes 1.5 minutes to travel 500m down a busy road. It stops at lights for 30 seconds, then continues on for 1 minute as it goes another 1km. Plot this on a distance/time graph. Distance (km) 0.5 1 1.5 Δd = 1km Steepest section is fastest Using the distance/time graph: What is the total distance traveled? 2. In what part of the trip is the car going the fastest? 3. What is the fastest speed? = 1.5 km Δt = 1min EXPT H/O speed challenge or Gather own data from 100m and draw some graphs = part 3 Time (min) 1 2 3 v = Δd / Δt v = 1km/1min In a distance/time graph the slope of the line = the speed of the object. 30

Interpret The Graph Below:

Interpret The Graph Below: The graph shows an object which is not moving (at rest). The distance stays the same as time goes by because it is not moving.

Interpret The Graph Below:

Interpret The Graph Below: The graph shows that the objects distance increases as time passes. The object is moving and so it has velocity. The straight line shows it is a constant (not changing).

Interpret The Graph Below:

Interpret The Graph Below: Just like the previous graph, this graph shows an object moving with constant velocity

Interpret The Graph Below:

Interpret The Graph Below: The curve in the graph shows that the objects velocity is changing as time passes. This is acceleration.

Interpret The Graph Below: In the first part of the graph the object is moving with constant velocity. In the second part of the graph the object is at rest (not moving). In the third part the object is again moving with constant velocity.

SPEED QUESTIONS What would these look like on a distance/time graph? 1. stopped 2. slow 3. fast 4. accelerating 40

Answer In Notes What is the speed of an object that goes 10 cm in 2 seconds How much time does it take for a person walking 500cm/s to travel 10000 cm What distance does a person run in 1 minute if they travel at 5 m/s Draw an Speed Graph and make one line for constant speed, one for acceleration, and one for stopped.

Interpret The Graph Below:

Interpret The Graph Below: The graph shows that the objects velocity does not change as time passes. It shows constant velocity.

Interpret The Graph Below:

Interpret The Graph Below: The graph shows that the objects velocity is increasing as time passes – it is accelerating. The straight line shows that it is constant acceleration.