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LESSON 1

LESSON 1. A TIP FROM THE TOP. Examiner Edward says: The key to success is being able to use the equations accurately and then write the correct units. Introducing……. The DATA SHEET You get this sheet with the exam

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LESSON 1

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  1. LESSON 1

  2. A TIP FROM THE TOP Examiner Edward says: The key to success is being able to use the equations accurately and then write the correct units

  3. Introducing…… The DATA SHEET You get this sheet with the exam Contains all of the equations that you will need to choose during the exam THEREFORE USE IT!!!

  4. TO GET A C

  5. Using the equationsTo get a Grade C A car has a mass of 10,000 kg. What is the weight of the car on Earth? (use gravitational field strength = 10N/kg) STEP 1: Choose the correct equation from the data sheet

  6. A car has a mass of 10,000 kg. What is the weight of the car on Earth? (use gravitational field strength = 10N/kg) Weight = Mass X Gravity = 10000 X 10 = 100000 What’s missing?

  7. THINK ABOUT IT I WONDER WHAT FORCES ARE MEASURED IN?

  8. NEWTONS

  9. A car has a mass of 10,000 kg. What is the weight of the car on Earth? (use gravitational field strength = 10N/kg) Weight = Mass X Gravity = 10000 X 10 = 100000N

  10. Lesson objectivesHave we hit any yet? ALL: Will BE ABLE to name the forces that act on objects and be able to draw them in the right direction on a force diagram (grade D) MOST: Will UNDERSTAND how to use simple equations to work out calculations (grade C) SOME: Will BE ABLE to rearrange the formula to get the correct equation and then apply to gain the correct answer with the correct units (grade B)

  11. TO GET A B

  12. A TIP FROM THE TOP Examiner Edward says: You will need to be able to rearrange the formula and use it

  13. Weight = Mass X Gravity Transfer the equation above into the triangle

  14. Weight Gravity Mass

  15. ERIC EARTH’S TIP OF THE DAY Use the cover up rule to work out the equation for MASS!!!

  16. TAKE YOUR HAND Weight Gravity Mass

  17. PLACE IT OVER MASS Weight Gravity Mass

  18. WHAT’S LEFT? Weight Gravity Mass

  19. Mass = Weight ÷ Gravity

  20. A man has a mass of 150kg and a weight of 240N when on the Moon. Write out the equation to work out the gravitational field strength and then use it to calculate the answer. Show all of your working Gravity = Weight ÷ Mass = 240 ÷ 150 = 1.6 N/kg

  21. Lesson objectivesHave we hit any yet? ALL: Will BE ABLE to name the forces that act on objects and be able to draw them in the right direction on a force diagram (grade D) MOST: Will UNDERSTAND how to use simple equations to work out calculations (grade C) SOME: Will BE ABLE to rearrange the formula to get the correct equation and then apply to gain the correct answer with the correct units (grade B)

  22. ANYONE WANT AN A?

  23. What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s? First one to spot the correct equation gets 25 Vivos

  24. But in this equation, there are more than 3 factors so we can’t use the equation triangle!!

  25. Don’t PANIC!!!!! BOB THE BUILDER “We can FIX IT……but you’ll need to watch carefully”

  26. STEP 1 • Write down the original kinetic energy equation • K.E = ½ x MASS X VELOCITY2 What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s?

  27. STEP 2 • The question wants you to work out the mass, so you must take everything else over to the other side • K.E = ½ x MASS X VELOCITY2 What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s?

  28. STEP 3 • Whatever the factors did on one side, they must do the opposite on the other. So ½ and velocity are multiplied by mass on one side so must be divided on the other side • K.E ÷ ( ½ x VELOCITY2) = MASS What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s?

  29. STEP 4 • Now use your rearranged equation to work out the question • K.E ÷ ( ½ x VELOCITY2) = MASS • 25000 ÷ ( ½ x 52) = MASS What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s?

  30. What is the mass of an elephant that has a kinetic energy of 25000J and moves with a velocity of 5 m/s? MASS = 2000 kg

  31. A TIP FROM THE TOP (I’M BACK) Examiner Edward says: The key to success is being to use the equations accurately and then write the correct units

  32. Usain is built like a unit and he just loves units!!!! And he wants you to feel the love too!Therefore every time we meet a new factor, write down the units at the back of your book! USAIN’S UNITS

  33. USAIN’S UNITS

  34. THEM UP

  35. Lesson objectivesHave we hit any yet? ALL: Will BE ABLE to name the forces that act on objects and be able to draw them in the right direction on a force diagram (grade D) MOST: Will UNDERSTAND how to use simple equations to work out calculations (grade C) SOME: Will BE ABLE to rearrange the formula to get the correct equation and then apply to gain the correct answer with the correct units (grade B)

  36. LESSON 2

  37. Look at the objects below and write down any force that you can think of that is acting on them “Be FORCEFUL!!”

  38. How many did you get? • gravity • friction • air resistance • water resistance • upthrust • thrust

  39. Homer’s Helpful hint Air resistance and water resistance are collectively known as DRAG

  40. Lesson objectivesHave we hit any yet? ALL: Will BE ABLE to name the forces that act on objects and be able to draw them in the right direction on a force diagram (grade D) MOST: Will UNDERSTAND how to use simple equations to work out calculations (grade C) SOME: Will BE ABLE to rearrange the formula to get the correct equation and then apply to gain the correct answer with the correct units (grade B)

  41. FORCE DIAGRAMS

  42. For each of these objects, draw a force diagram with the direction of the acting force shown

  43. “The sum of the forward forces acting on an object subtract the backward forces” WORDS RESULTANT FORCES

  44. TASK Work out the following resultant forces

  45. Lesson objectivesHave we hit any yet? ALL: Will UNDERSTAND the definition of a resultant force and will BE ABLE to work out the resultant forces in given situations (grade C) MOST: Will UNDERSTAND how different resultant forces affect the movement of an object (grade B) SOME: Will BE ABLE to explain what happens to an object with reference to the resultant force (grade A)

  46. Scenario 1 Friction 8N Thrust 10N Drag 2N So resultant force = ON. Car will stay moving at a constant speed

  47. Scenario 2 Friction 6N Thrust 10N Drag 2N So resultant force = 2N forwards. Car will accelerate

  48. Scenario 3 Friction 11N Thrust 10N Drag 4N So resultant force = 5N backwards. Car will decelerate

  49. If the forward forces are equal to the backward forces, then they are _____________ and the resultant force = _____N. In this case, the object will continue doing as it was - this could be staying still or to continue moving at a ___________ speed. If forces are ________, then the object changes speed and this is affected by the _____________ force. If there is more force ________, the resultant force will be ___________ and the object accelerates. If there is more force backwards, the resultant force is ___________ and then the object will________________.

  50. If the forward forces are equal to the backward forces, then they are balanced and the resultant force = 0N. In this case, the object will continue doing as it was - this could be staying still or to continue moving at a constantspeed. If forces are unbalanced, then the object changes speed and this is affected by the resultant force. If there is more force forwards, the resultant force will be positive and the object accelerates. If there is more force backwards, the resultant force is negative and then the object willdecelerate.

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