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Day 1 - Do Now

Day 1 - Do Now. Take 1 minute to answer the question: Why would we want to measure force? (i.e. under what circumstances is measuring force useful?) Please write an example. Sir Isaac Newton. Newton’s 2 nd Law.

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Day 1 - Do Now

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  1. Day 1 - Do Now • Take 1 minute to answer the question: • Why would we want to measure force? (i.e. under what circumstances is measuring force useful?) • Please write an example.

  2. Sir Isaac Newton

  3. Newton’s 2nd Law • Newton’s 2nd Law gives us the ability to calculate how much force is required to move an object

  4. The formula • F = m X a (force = mass times acceleration) F = ma

  5. Playing with the formula F F • F= ma OR m= -------- OR a= --------- a m   • Units: unit for force is N (Newton) m = kg a = m/sec2 Newton = Kg xm sec2

  6. Formula Trick Cover the symbol you are trying to find!

  7. 2nd Law Quick Practice • A 100 Kg linebacker hits the running back while accelerating at 3 m/s2. What is the force the linebacker hits the running back? Answer in Newtons

  8. Quick Practice F = m x a mass = 100 Kg accel. = 3 m/s2 F = 100 Kg x 3 m/s2 F = 300 Kg x m / s2

  9. Day 2 - Do Now • Please take two minutes to answer this question: • What is the funniest or most fun race you have ever participated in or have seen?

  10. Wagon Race

  11. Scenario • One Saturday morning you and your eleven friends decide to have a wagon race.  Each wagon team has a total of four people, arranged in the following manner and shown below in the diagrams:

  12. Wagon 1 – 2 people pushing the wagon and 2 people sitting in the wagon • Wagon 2 - 3 people pushing the wagon and 1 person sitting in the wagon • Wagon 3 - 1 person pushing the wagon and 3 people sitting in the wagon

  13. WAGON #1 Force of Each Person Pushing the Wagon Person number Force (N) 1 53 2 55

  14. WAGON #1 Mass of Each Person in the Wagon Person number Mass (Kg) 3 31 4 37

  15. WAGON #2 Force of Each Person Pushing the Wagon Person number Force (N) 5 55 6 31 7 11

  16. WAGON #2 Mass of Each Person in the Wagon Person number Mass (Kg) 8 40

  17. WAGON #3 Force of Each Person Pushing the Wagon Person number Force (N) 9 80

  18. WAGON #3 Mass of Each Person in the Wagon Person number Mass (Kg) 10 37 11 56 12 29

  19. The following formulae may be used in this task: F = ma d = ½ at2 v=at

  20. Units Symbol Unit Distance d m (meter) Mass m kg (kilogram) Velocity v m/s Acceleration a m/s2 Time s s(second) Force (Newton) N kg . m/s2

  21. Step 1 1. Using the information contained in the prompt, calculate the acceleration of each wagon.  Show all work and be sure to include all units in your calculations and answers.

  22. The Accelerations F=ma ΣF=(Σm)a Ex. F1+F2=(m1+m2)a Σ = Summation or Sum Of or Total Of

  23. Force on Wagon #1 Force of Each Person Pushing the Wagon Person number Force (N) 1 53 2 55 ΣF= F1+F2 = 53N+55N = 108N

  24. Mass of Wagon #1 Mass of Each Person in the Wagon Person number Mass (kg) 3 31 4 37 Σm= m3+m4 = 31kg+37kg = 68kg

  25. Acceleration of Wagon #1 ΣF=(Σm)a = (F1+F2)=(m1+m2)a Convert N to kg . m/s2 (53N545N)=(53kg . m/s2 + 55kg . m/s2) (53kg . m/s2 + 55kg . m/s2)=(31kg+37kg)a (108kg . m/s2)=(68kg)a (108kg . m/s2) =(68kg)a = 1.59 m/s2 (68kg) (68kg)

  26. Force on Wagon #2 Force of Each Person Pushing the Wagon Person number Force (N) 5 55 6 31 7 11 ΣF= F5+F6+F7 = 55N+31N+11N = 97N

  27. Mass of Wagon #2 Mass of Each Person in the Wagon Person number Mass (Kg) 8 40 Σm= m8 = 40kg

  28. Acceleration of Wagon #2 ΣF=(Σm)a = (F5+F6+F7)=(m8)a Convert N to kg . m/s2 (55N+31N+11N)=(55kg . m/s2 + 31kg . m/s2 +11kg . m/s2) (55kg . m/s2 + 31kg . m/s2 +11kg . m/s2)=(40kg)a (97kg . m/s2)=(40kg)a (97kg . m/s2) =(40kg)a = 2.425 m/s2 (40kg) (40kg)

  29. Force of Wagon #3 Force of Each Person Pushing the Wagon Person number Force (N) 9 80 Σm= m9 = 80kg

  30. Mass on Wagon #3 Mass of Each Person in the Wagon Person number Mass (Kg) 10 27 11 46 12 19 ΣF= F10+F11+F12 = 27N+46N+19N = 92N

  31. Acceleration of Wagon #3 ΣF=(Σm)a = (F9)=(m10+m11+m12)a Convert N to kg . m/s2 (100N)=(100kg . m/s2) (100kg . m/s2)=(27kg+46kg+19kg)a (100kg . m/s2)=(92kg)a (100kg . m/s2) =(92kg)a = 1.0870 m/s2 (92kg) (92kg)

  32. Day 3 - Do Now • What kind of information can you calculate using the formula F=ma? • How can you use these problems in real life?

  33. Table Assumptions 2a.   Assuming that each wagon maintains a constant acceleration for five seconds, construct a table which compares the speed and time of each wagon.  Your table should represent every second from resting to five seconds.

  34. Table

  35. Using the Table 2b. Using the table you created, construct a single graph plotting the speed vs. time data for each of the three wagons.

  36. GRAPHING

  37. Calculating distance • What is the distance travelled by each wagon? Wagon 1 • d = ½ at2 • d = ½ (1.59 m/s2) 5 s 2 • d = ½ (1.59 m/s2) (25 s2) • d= ½ (39.75) • d= 19.88

  38. The race! • If a 200 meter race was held, which wagon would win? • First of all how long is 200 meters? Bolt! • Use words to describe your thinking and relate it to Newton’s second law: • Acceleration, mass and force!!!

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