What is Energy? 1. Energy is the ability to do 2. Energy is a property of objects that can be 3. The unit for energy is the _ 4. What is your highest score in What is Energy - Gameshow? 5. What is your highest score in Potential & Kinetic - Gameshow? 6. What do you always know about the direction of friction? 7. Friction creates energy. 8. Using a dictionary/online, "kinetic" means 9. Using a dictionary/online, "static" means 10. List 3 situations where friction may be considered a detriment or "bad" thing 11. List 3 situations where friction may be considered an asset or "good" thing 12. Describe the properties of an object whose motion will be greatly affected by wind resistance. 13. Consider the Bobsled Energy Media. a) By releasing the bobsled, you convert the energy into energy. b) The higher the ramp, the greater the amount of energy at the top. c) The higher the ramp, the greater the resulting energy at bottom. d) The greater the "surface friction," the faster/slower the energy is converted to heat. e) The greater the "wind resistance friction," the faster/slower the energy is converted to heat.1. Saying that "Energy is Conserved" means that energy is never or 2. When we say that something "lost energy" we really mean that some of the energy was converted into a form that is to us. 3. A skier at the bottom of a hill has 900J of kinetic energy. After sliding a little way along the flat, the kinetic energy has decreased to 300J. a) With a decreased kinetic energy, what do you know about the skier's velocity? Why? b) With the skier sliding on a flat surface, is there any change in gravitational potential energy? How do you know? c) How much energy was "lost" due to friction and sound? (Use Ebefore = Eafter). Show all steps. 4. A skier on a hill has 4000J of kinetic energy and 3000J of potential energy. After sliding down the hill a little way, their potential energy is 2000J. a) Since they slid "down" the hill, what do you expect for change in potential energy (positive or negative)? Why? b) Assuming that there is no loss due to friction, what would be the kinetic energy at the second position? (Use Ebefore = Eafter and show all steps) c) Since there's always "some" friction loss, would the "actual" kinetic energy be less or more than your answer in b)?5. What is the equation used for calculating efficiency? 6. In this equation, what do we mean by "Useful Energy Out?" 7. In the equation, what do we mean by "Energy In?" 8. Because we know that energy never "appears from nowhere," we know that efficiency can never be greater than % 9. A particular light bulb converts energy so that every 100J of electrical energy coming in creates 8J of light energy and 92J of heat energy. A Sankey Diagram can be used to show the flow of energy through the light bulb. Place an to the left of each incorrect Sankey Diagram shown below, and a V to the left of the correct diagram. Then briefly explain why each diagram is incorrect. Correct or Sankey Diagram Why Incorrect? Incorrect? X or V 80 Light Energy Blectrical Energy 121 Hem Esargy 1001 Al Light Energy Electrical Energy 971 Heat Energy Bi Light Energy 1001 Electrical Energy 921 Heat Energy 1001 Electrical Energy 921 Heat Energy BJ Light Energya) What would (normally) be considered the "useful energy?" for this light bulb b) What would be the "Energy in?" c) What is the efficiency of this light? Show original equation and steps. d) If you were using this bulb to "heat" then what would be the "useful energy?" e) If you were using this bulb to "heat" then what would be the "efficiency?" Show original equation and steps. 0. A roller coaster uses 800 000 J of energy to get to the top of the first hill. During this climb, it gains 500 000 J of potential energy and pauses (velocity = 0) for a fraction of a second at the very top before heading down the other side. a) Draw a Sankey diagram showing the flow of energy during the roller coaster's climb. b) What's the kinetic energy at the very top? How do you know? c) What would be the "useful energy" during its climb to the top? How do you know? d) How much energy was "lost" due to friction (heat) and sound? (Use Ebefore = Eafter). e) Calculate the efficiency of the roller coaster during this part of the ride (the climb).11. The roller coaster from the previous question is finally released from its pull up the first climb (where its potential energy is 500 000J) and begins its decent downwards. The roller coaster heads down and levels out as it hits the original level. a) Since they are back at the original level, what do we know about the potential energy at this point? Why? b) If we know that we lost 200 000J to heat energy during this first drop, what is the kinetic energy at the bottom? (Use Ebefore = Eafter) c) What is the efficiency of the roller coaster during this part of the ride? 12. Discuss how improving energy "efficiency" can improve the world. Provide examples