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Energy

Energy. Work Makes Me MAD!!!. Kinetic Energy. Potential Energy. Conservation of Energy. Physics is Phun!. Work Makes Me MAD!!!. Kinetic Energy. Potential Energy. Conservation of Energy. Physics is Phun!. 5 pt. 5 pt. 5 pt. 5 pt. 5 pt. 10 pt. 10 pt. 10 pt. 10 pt. 10 pt.

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Energy

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  1. Energy

  2. Work Makes Me MAD!!!

  3. Kinetic Energy

  4. Potential Energy

  5. Conservation of Energy

  6. Physics is Phun!

  7. Work Makes Me MAD!!! Kinetic Energy Potential Energy Conservation of Energy Physics is Phun! 5 pt. 5 pt. 5 pt. 5 pt. 5 pt. 10 pt. 10 pt. 10 pt. 10 pt. 10 pt. 15 pt. 15 pt. 15 pt. 15 pt. 15 pt. 20 pt. 20 pt. 20 pt. 20 pt. 20 pt. 25 pt. 25 pt. 25 pt. 25 pt. 25 pt.

  8. 1-5 When energy is added to an object, what kind of work is done? A) positive B) negative C) zero D) not enough info 5 pt.

  9. 1-5A When energy is added to an object, what kind of work is done? A) positive 5 pt.

  10. 1-10 Is the work done on the object pictured below positive or negative? Force distance 10 pt.

  11. 1-10A Is the work done on the object pictured below positive or negative? Force distance Zero, since the force and distance are at right angles. 10 pt.

  12. 1-15 How much work is done by a car’s engine when it pushes with a force of 1450 N through a distance of 200 meters? 15 pt.

  13. 1-15A How much work is done by a car’s engine when it pushes with a force of 1450 N through a distance of 200 meters? Work = Force x distance Work = (1450 N)(200 m) = 290,000 J 15 pt.

  14. 1-20 How many watts are expended when a 100-N person walks 3.5 meters up a flight of stairs in 14 seconds? 20 pt.

  15. 1-20A How many watts are expended when a 100-N person walks 3.5 meters up a flight of stairs in 14 seconds? Work = Force x distance Work = (100 N)(3.5 m) = 350 J Power = Work / Time Power = (350 J)/(14 sec) = 25 Watts 20 pt.

  16. 1-25 Suppose that a block of weight 300-N is lifted through a height of 5 meters by pushing it up a ramp 16.5 meters long. How hard must the block be pushed up the ramp? F 5 m 16.5 m 25 pt.

  17. 1-25A Suppose that a block of weight 300-N is lifted through a height of 5 meters by pushing it up a ramp 16.5 meters long. How hard must the block be pushed up the ramp? Energy needed = weight x height = (300 N)(5 m) = 1500 J Work on Ramp = 1500 J Work = Force x distance Force = Work / distance = (1500 J)/(16.5 m) = 90.9 Newtons F 5 m 16.5 m 25 pt.

  18. 2-5 Negative work is done on a rolling bowling ball. What happens to the kinetic energy of the ball? A) KE increases B) KE does not change C) KE decreases D) not enough info 5 pt.

  19. 2-5A Negative work is done on a rolling bowling ball. What happens to the kinetic energy of the ball? C) KE decreases 5 pt.

  20. 2-10 True or False: It is possible for an object to have a negative kinetic energy. 10 pt.

  21. 2-10A True or False: It is possible for an object to have a negative kinetic energy. False 10 pt.

  22. 2-15 What is the KE of a car with mass 1200-kg that is moving at 50 m/sec? 15 pt.

  23. 2-15A What is the KE of a car with mass 1200-kg that is moving at 50 m/sec? KE = 1/2mv2 KE = 1/2 (1200 kg)(50 m/s)2 KE = 1,500,000 Joules 15 pt.

  24. 2-20 Two identical cars are traveling down the road -- one moving at twice the speed of the other. If both apply the brakes, what will happen? A) they both travel the same distance B) the faster car will move twice as far C) the faster car will move four times as far D) not enough info 20 pt.

  25. 2-20A Two identical cars are traveling down the road -- one moving at twice the speed of the other. If both apply the brakes, what will happen? C) the faster car will move four times as far 20 pt.

  26. 2-25 A rocket of mass 250-kg is pushed by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off? 25 pt.

  27. 2-25A A rocket of mass 250-kg is pushed by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off? Work = Change in KE ==> Fd = 1/2mv2 (10,000 N)(12,000 m) = 1/2 (250 kg)v2 v = √[2(10,000 N)(12,000 m)/250 kg] v = 980 m/sec 25 pt.

  28. 3-5 How do you calculate gravitational potential energy (GPE)? 5 pt.

  29. 3-5A How do you calculate gravitational potential energy (GPE)? GPE = weight x height = mgh 5 pt.

  30. 3-10 What is the GPE of a 50-kg object placed at a height of 10 m? 10 pt.

  31. 3-10A What is the GPE of a 50-kg object placed at a height of 10 m? GPE = mgh = (50 kg)(10 m/s2)(10 m) GPE = 5,000 Joules 10 pt.

  32. 3-15 A perfect pendulum swings from rest. How high does it go before it stops? A) lower than originally B) the same height as originally C) higher than originally D) not enough info 15 pt.

  33. 3-15A • A perfect pendulum swings from rest. How high does it go before it stops? • the same height as originally 15 pt.

  34. 3-20 An elevator of 550-kg goes from the first to the fourth floor. If each floor is 4 meters, how much GPE does the elevator gain? 20 pt.

  35. 3-20A An elevator of 550-kg goes from the first to the fourth floor. If each floor is 4 meters, how much GPE does the elevator gain? Weight = 550 kg * 10 m/s = 5,500 N GPE = weight x height = (5,500 N)(3 x 4 m) (it’s 3 flights from 1st to 4th floor) GPE = 66,000 Joules 20 pt.

  36. 3-25 Your Team may wager from 0-50 pts. You must make your wager BEFORE the Daily Double is revealed!!! 25 pt.

  37. 3-25A Daily Double Daily Double How much power does the engine of a 2300-kg elevator put out if it climbs through 38-m in one minute? GPE = (2300 kg)(10 m/s2)(38 m) = 874,000 J Power = GPE / Time = (874,000 J)/(60 sec) Power = 14,567 Watts Daily Double

  38. 4-5 If the universe began during the Big Bang 15 billion years ago with an energy of 516 gadzillion Joules, how much energy is there in the universe right now? 5 pt.

  39. 4-5A If the universe began during the Big Bang 15 billion years ago with an energy of 516 gadzillion Joules, how much energy is there in the universe right now? 516 gadzillion Joules 5 pt.

  40. 4-10 When a car slows down to a stop where does all of its previous KE go? A) it turns into heat B) braking energy C) into total mechanical energy D) not enough info 10 pt.

  41. 4-10A • When a car slows down to a stop where does all of its previous KE go? • it turns into heat 10 pt.

  42. 4-15 When a diver who weighs 650-N jumps from a 10-m high diving platform, how much KE do they hit the water with? 15 pt.

  43. 4-15A When a diver who weighs 650-N jumps from a 10-m high diving platform, how much KE do they hit the water with? GPEinitial = KEfinal KEfinal = (650 N)(10 m) = 6500 J 15 pt.

  44. 4-20 When jumping up and down on a trampoline, the 450-N jumper leaves the trampoline with a KE of 3800 J. How high do they travel?

  45. 4-20A When jumping up and down on a trampoline, the 450-N jumper leaves the trampoline with a KE of 3800 J. How high do they travel? KEinitial = GPEfinal = mgh 3800 J = (450 N) h h = (3800 J)/(450 N) = 8.44 m 20 pt.

  46. 4-25 A 2-kg ball slides from rest down a 5-m tall incline as shown. When it is halfway down, how fast is it going? 25 pt.

  47. 4-25A A 2-kg ball slides from rest down a 5-m tall incline as shown. When it is halfway down, how fast is it going? GPEinitial = KE + GPE (2kg)(10m/s2)(5m) = 1/2 (2kg)v2 + (2kg)(10m/s2)(2.5m) 100 J = v2 + 50 J v = √(50) = 7.1 m/sec 25 pt.

  48. 5-5 Where on Earth would you have the greatest gravitational potential energy? 5 pt.

  49. 5-5A Where on Earth would you have the greatest gravitational potential energy? Mount Everest 5 pt.

  50. 5-10 Name the character and movie that produced this famous quote: “A wizard is never late… he arrives precisely when he means to.” 10 pt.

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