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Did you reference t his? If not, do so now!

Did you reference t his? If not, do so now!. 65 + 20 = 85 m/s east. 8 5 + 20 = 105 m/s east. 105 + 20 = 125 m/s east. & / or. & / or. & / or. Take out your POGIL HW from last night…. We are rapidly reviewing #10-24. 10. True or false – Acc. Is a vector quantity- EXPLAIN . True

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Did you reference t his? If not, do so now!

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  1. Did you reference this? If not, do so now!

  2. 65 + 20 = 85 m/s east 85 + 20 = 105 m/s east 105 + 20 = 125 m/s east

  3. & / or & / or & / or

  4. Take out your POGIL HW from last night… • We are rapidly reviewing #10-24

  5. 10. True or false – Acc. Is a vector quantity- EXPLAIN • True • False • Not enough info • Not sure Acceleration is the CHANGE IN VELOCITY divided by time. Since Velocity is a vector, so is acceleration. Add this to your T chart!

  6. 11. A car is traveling around a curve on a highway, at a constant speed – is it accelerating? • Yes • No • Not enough info • Not sure

  7. 11. A car is traveling around a curve on a highway, at a constant speed – is it accelerating?

  8. 12. What does the term RATE mean? • Anything divided by time • It tells you HOW FAST something happens • Some examples so far are… • Speed • Rate at which distance is coverd • Velocity • Rate at which position changes • Or rate at which displacement happens • Acceleration • Rate at which velocity changes

  9. 13. So… acceleration is the rate at which _____________ changes • Speed • Velocity • Distance • Displacement • Not enough info • Not sure

  10. 14. Which of the following represent units of acceleration? (ignore direction) • 5 km • 15 km s • 25 s/km • 55 km s2 • 2 miles per hour per second • 5 kmh.s • D & E • D & F • E & F • D, E & F

  11. 14b. Why did you answer the way you did in 14a? Acceleration is the RATE at which velocity changes. Velocity is the RATE at which position changes (or the rate at which displacement occurs) So, acceleration needs 2 units of time!

  12. EXTRA QUESTION What do these accelerations mean? In other words…by looking at these accelerations, can you conclude the object is speeding up? Slowing down? How? By how much, how often? Etc…interpret in WORDS

  13. What do these accelerations mean? In other words…by looking at these accelerations, can you conclude the object is speeding up? Slowing down? How? By how much, how often? Etc…interpret in WORDS This is the same as saying 55 km s .s Every second, the velocity is INCREASING by 55 km/s. (I know it’s increasing because it’s a POSITIVE acceleration, so it must be speeding up.

  14. What do these accelerations mean? In other words…by looking at these accelerations, can you conclude the object is speeding up? Slowing down? How? By how much, how often? Etc…interpret in WORDS Every second, the velocity is INCREASING by 2 miles per hour. (I know it’s increasing because it’s a POSITIVE acceleration, so it must be speeding up.

  15. What do these accelerations mean? In other words…by looking at these accelerations, can you conclude the object is speeding up? Slowing down? How? By how much, how often? Etc…interpret in WORDS Every second, the velocity is INCREASING by 5 km/h. (I know it’s increasing because it’s a POSITIVE acceleration, so it must be speeding up.

  16. 15. Why is acceleration a rate of a rate? • Velocity • Rate at which position changes • Or rate at which displacement happens • Acceleration • Rate at which velocity changes • Think of it like this. Velocity (rate) is how fast something is going (i.e. meters/second )Acceleration (rate) is how quickly velocity (rate) changes. i.e. meters/second/second. Acceleration is the rate of change of a rate of velocity... a rate of a rate.

  17. Positive Negative ZERO – careful here! ZERO – careful here!

  18. Debrief • 2 minutes to ask a neighbor / teacher about… • any questions from #10-15 • Or any troublesome problems from #16-24 (we’re clicker reviewing these next!)

  19. 16. True or False: Acceleration ONLY occurs if the speed INCREASES • True • False • Not enough info to say • Not sure

  20. 17. If velocity in a vehicle is CONSTANT, is the vehicle accelerating? • Yes • No • Not enough info to say • Not sure

  21. 18. Suppose you are driving a car at a constant velocity of 50 mi/h. What is your acceleration? • 0 • Less than 50, but not 0 • More than 50 • Not enough info to say • Not sure

  22. 19. Suppose a car moving in a straight line steadily increases its speed each second, first from 35 to 40 km/h, then from 40 to 45 km/h, then from 45 to 50 km/h, What is its acceleration? • 0 • 5 km/h s • Less than 5 km/h s • More than5 km/h s • Not sure

  23. 19. Suppose a car moving in a straight line steadily increases its speed each second, first from 35 to 40 km/h, then from 40 to 45 km/h, then from 45 to 50 km/h, What is its acceleration? 5 km/h s Every second, it is INCREASING its velocity by 5 km/h. No math needed! Use common sense! THINK about what the problem is TELLING YOU!

  24. 20. In 5 seconds a car moving in a straight line increases its speed from 50 km/h to 65 km/h. During those same 5 seconds, a truck goes from rest to 15 km/h. What’s the acceleration of the car? • 3 km/h • 5 km/h • 15 km/h • 3 km/hs • 5 km/hs • 15 km/hs • None of the above • Not sure

  25. 20. In 5 seconds a car moving in a straight line increases its speed from 50 km/h to 65 km/h. During those same 5 seconds, a truck goes from rest to 15 km/h. What’s the acceleration of the Truck? • 3 km/h • 5 km/h • 15 km/h • 3 km/hs • 5 km/hs • 15 km/hs • None of the above • Not sure

  26. 20. In 5 seconds a car moving in a straight line increases its speed from 50 km/h to 65 km/h. During those same 5 seconds, a truck goes from rest to 15 km/h. Which has the larger acceleration? • Car • Truck • Same • Not sure

  27. So…You CAN’T assume that the faster you are going, the higher your acceleration. • Acceleration is NOT how fast you’re moving! • Acceleration is the change in velocity divided by the time interval • Acceleration describes how quickly velocity CHANGES • Having a HIGH acceleration does not mean HOW QUICKLY you can move… • It means HOW QUICKLY you can change your velocity.

  28. 21. Is it possible to be moving but not accelerating? • Yes • No • Not enough info to say • Not sure

  29. If you’re NOT doing any of these things, you’re not accelerating!

  30. 22. Why is it that an object can accelerate while traveling at constant speed, but not at constant velocity? Because it can travel at a constant speed and CHANGE DIRECTION (meaning it’s accelerating!) But…constant velocity means it’s not changing velocity, and therefore not accelerating

  31. 23. Light travels in a straight line at a constant speed of 300,000 km/s. What is the light´s acceleration? • 0 • Less than 300,000 but not 0 • More than 300,000 • Not enough info to say • Not sure

  32. 24. Which has more acceleration when moving in a straight line- a car increasing its speed from 50 to 60 km/hr, or a bicycle that goes from zero to 10 km/hr in the same time? • Car • Bike • Same • Not enough info to say • Not sure

  33. 24. Which has more acceleration when moving in a straight line- a car increasing its speed from 50 to 60 km/hr, or a bicycle that goes from zero to 10 km/hr in the same time? • Car • Bike • Same • Not enough info to say • Not sure Same CHANGE IN VELOCITY, divided by the SAME TIME.

  34. Now, take out your HW from last night… p. 25, #9-143 minutes to check your neighbor with #9-14 before a rapid review

  35. 9. What quantity describes how quickly you change how fast you’re traveling, or how quickly you change direction? • Speed • Velocity • Acceleration • Distance • Displacement • Not sure

  36. 10. Acceleration is the rate at which what CHANGES?? • Speed • Velocity • Acceleration • Distance • Displacement • Not sure

  37. 11. What is the acceleration of a car that travels in a straight line at a constant speed of 100 km/h in 10 s? • 0 • 10 km/hs in a straight line • 100 km/hs in a straight line • 1000 km/hs in a straight line • Answer is not listed • Not sure

  38. 12. What is the acceleration of a car moving along a straight-line path that increases its speed from zero to 100 km/h in 10s? • 0 • 10 km/hs in a straight line • 100 km/hs in a straight line • 1000 km/hs in a straight line • Answer is not listed • Not sure

  39. 13. By how much does the speed of a vehicle moving in a straight line change each second when it is accelerating at… 2 km/ h/s? At 4 km/h/s? At 10 km/h/s? 2 km/h 4 km/h 10 km/h

  40. 14. Why does the unit of time enter twice in the unit of acceleration? Because acceleration is a rate of a rate. Or, once for velocity and again for accleration Etc.

  41. Now, onto the math… • #25-28 in your POGIL • Try # 25 on your own based on what we practiced with

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