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Back seat of an F-18. SPEED. http://alt.coxnewsweb.com/ajc/swf/blueangels/blueangels.swf. Question #8. Are we ever really standing still?. Is motion relative? Yes or No?. Yes, All things are in motion. . The sun orbits the center of the galaxy, our galaxy and

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  1. Back seat of an F-18 SPEED http://alt.coxnewsweb.com/ajc/swf/blueangels/blueangels.swf

  2. Question #8 Are we ever really standing still? Is motion relative? Yes or No?

  3. Yes, All things are in motion. • The sun orbits the center of the • galaxy, our galaxy and • Andromeda are moving toward • one another, most of the other • galaxies are moving away. You may be perfectly still yet the earth is spinning on its axis and orbiting the sun.

  4. So to measure motion in a meaningful way, we measure it relative to the observer or another object we consider not to be moving. When you pass a car on the highway moving in the same direction, you may be going 70mph, and the other car 65mph. But your speed relative to the other car is 5mph. When the shuttle docks with the space station the two orbiting objects approach one another at a very slow speed relative to one another, but both are orbiting at 17,000mph relative to the surface of the earth.

  5. Main IDEAS • Motion is a change in position relative to your surroundings. • An object moves when it speeds up, slows down or changes direction.

  6. What’s a Frame of Reference?

  7. A B C

  8. BACKGROUND OR OBJECT USED FOR COMPARISON

  9. Measuring Motion SPEEDrate at w/c an object moves Distance (D) Speed = Time (T)

  10. Another way to express this is in a “formula triangle” like this: d s t

  11. SPEED IS…. Inversely Proportional toTIME An ant crawled 12 inches in 10 seconds. A second ant crawled 24 inches in 10 seconds. Compare the speed of the ants.

  12. DIRECTLY PROPORTIONAL TO DISTANCE A plane flew 220 meters in 1 second. A second plane flew 220 meters in 2 seconds. Compare their speeds.

  13. DISTANCE Length between two places Distance = speed x time D= ST Expressed in km (1000m)

  14. TIME = T d s

  15. STEPS IN PROBLEM SOLVING • STEP 1. Write the formula • STEP 2. Substitute given numbers and units • STEP 3. Solve for the unknown.

  16. CONSTANT SPEED SPEED THAT DOES NOT CHANGE

  17. CONSTANT SPEED

  18. SAMPLE PROBLEM: At what speed did a plane fly if it traveled 1760 meters in 8 seconds?

  19. SOLUTION Step 1.Speed = Distance/Time Step 2. Speed = 1760 meters/ 8sec Step 3. Speed = 220 m/sec

  20. SAMPLE PROBLEMS: 1. A car travels 240 kilometers in 3 hours. What is the speed of the car during that time? ANSWER: S= d/t S= 240 km/3 hr 80 Km/Hr

  21. The speed of a cruise ship is 50 km/hr. How far will the ship travel in 14 hours? Answer: D = ST 700 km

  22. AVERAGE SPEED TOTAL DISTANCE / TOTAL TIME AVERAGE total distance traveled SPEED time =

  23. AVERAGE SPEED

  24. A car travels 200 m in 10 seconds. What is the average speed of the car? ANSWER: Ave speed= total d/total time = 200m/10s 20 m/s

  25. Definitions: A change in position in a certain amount of time is __________. __________________ is the rate at which an object moves and is determined by dividing ____________ by _____________. _________________________ is speed that does not change. _________________________ is calculated by dividing the total distance by the total time.

  26. Image source: http://www.myteacherpages.com/

  27. http://www.youtube.com/watch?v=arD374MFk4w&feature=player_embeddedhttp://www.youtube.com/watch?v=arD374MFk4w&feature=player_embedded http://www.youtube.com/watch?v=crjU5hu2fag&feature=player_embedded

  28. SPEED WORKSHEET Complete for homework

  29. 2. Describe the motion shown in the graph: 3.Calculate the average speed for the graph – how does this value compare to your calculations above? 4. How far would Ken travel if he walked for another hour (60 minutes)? • Calculate the speed at each point on the y-axis

  30. 2. Describe the motion shown in the graph: 3.Calculate the average speed for the graph – how does this value compare to your calculations above? 0.075 km/min 3. How far would Ken travel if he walked for another hour (60 minutes)? 13.5 km • Calculate the speed at each point on the y-axis

  31. 5.Describe the motion shown in the graph 6.How many different rates are shown? Label them using A, B, . . . . . • 7. Calculate the speeds for the different segments of the journey (Hint - you will have to use change in distance!) 8. What is the average speed for the entire trip? How does the value compare to your calculations above? 9. Can you predict how far Michelle will travel if she travels for another 2 hours? Why or why not? What additional information do you need?

  32. 5.Describe the motion shown in the graph (moving at varying speed) 6.How many different rates are shown? Label them using A, B, . . . . . • 7. Calculate the speeds for the different segments of the journey (Hint - you will have to use change in distance!) 8. What is the average speed for the entire trip? How does the value compare to your calculations above? 11.7 or 12 km/h 9. Can you predict how far Michelle will travel if she travels for another 2 hours? Why or why not? What additional information do you need?

  33. Summary of Force: http://www.brainpop.com/science/motionsforcesandtime/force/ Review: file://///server14/stares$/Middle%20School/Science/Grade%20Levels/Grade%207/7.2%20Innovation/Forces/Forces%20Review%20Quiz/Forces%20Review.htm

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