WORK, ENERGY AND POWER ! 12. Explain why their work was larger/smaller/same. Show ALL WORK with formulas, math, units, etc. in spaces provided. 13. Which student in your group used the most POWER? Put ANSWERS in the DATA TABLE and/or in the blanks provided. Complete this work sheet after you are done with lab. 14. Explain why their power usage was greater/smaller/same.. 15. If a power company paid you $1.00 per kilowatt of power you produce (1 kw = 1000 Joules / 1. What is your weight in pounds? Ibs second or 1kw = 1000 Watts), how much money would you make for this climb? Calculate here, 2. What is your weight in kilograms? kg and put in data table A. Use 2.2 Ibs = 1 kg conversion factor, Show calculation here : Calculate each of the member's weight in kg and fill put in data table A. 16. Why you did not take the length of the stairs (distance of the plain surface) to calculate the work done? Explain in details! DATA TABLE A 3. What is your weight in Newton's? Remember that weight in Newton is mass in kg (from #2) times acceleration due to gravity. (W= mg) and g =9.8 m/s'. Show your work here, and put in data table A. NAME MASS WT. Vertica WORK PE t TIME POWER $ for kW-hrs 4. Now find out the information of the stairs of your house or if you do not have staris, find a stairin in kg in N I d (ht.) done by top in to go in climb your near by place and get the following information: in m you up in Watts in J 5. What is the vertical distance (height) of one average step? [This question is about the stairs] (If you measure in cm, convert to m) m 5. How many steps are there? X steps 6. What is the vertical distance (height) of the steps? m 7. Have your partner time you as you climb the stairs at a steady pace. Be careful NOT TO TRIP! Time each of the group members one by one. Put in Table A. 8. How much WORK do you do climbing the stairs? (W = F (cos 0) d ). Force will be your WEIGHT in 17. Would all group members hit the ground with the SAME FORCE after free-falling? Why or why Newton's from #3 times the vertical distance (height) of the steps. What about the angle? Calculate not? here, and put in data table A. 18. THINK about this and tell me... AFTER you jumped off and free-fell to the ground from the top . How much POTENTIAL ENERGY do you have at the TOP of the stairs, relative to the ground? of the stair (do not try this, this is just a thought experiment), WHAT would happen to the (PE = mg th) Calculate here, and put in data table A. ENERGY that was Potential at the top, and Kinetic just before you hit the ground??! In other words, WHERE would the energy "go"? 10. How much POWER did you each use? (Power = Work/time or P = Fd/t) Calculate here, and put in data table A. [This unit will be J/s or Watts!] 19. Find out what would be your speed when you are about to hit the ground if you jump from the top of the stairs. 11. Which student in your group did the MOST WORK? 220. Example: Suppose a 1.5 kW electric heater runs for 3 hours, P = 1.5 kW, and = 3 h. [As you know, W=E, and P=W/t. So Work (or energy) is = Power X time.] Therefore the energy E in kilowatt-hours for this example problem is: E = Pt= 1.5 x 3 = 4.5 kWh Now: Calculate your energy expended in kW- hrs going up the stairs and put into last column of Data Table A. Show work here! members of group. 21. Suppose, you just had a slice of pizza (shown below Domino's and Pappa John's), find out how 170 many times you need to climb the stairs to burn the equal amount of calories for two different calories slices of pizza? Show your work in detail here (provide the result for each individual here): Suggest that is it easy to loose your weight via work out or via dieting based upon your result! Serving size 1 X slice, 1/8 pizza (2.2 oz) 170 Papa John's Garden Fresh Pizza w/ Thin Crust X Convert joule to calorie [nutritional] Nutrition Facts Serving Size 1 slice 1 slice = 1/8 pizza 711000 joule Amount Per Serving Calories 210 169.81943250 calorie [nutritional] % Daily Value* Total Fat 10g 15% Convert Saturated Fat 4g 20% Trans Fat 0g Cholesterol 20mg 7% Nutrition races Sodium 460mg 20% Total Carbohydrate 21g 7% Calories 170 (711 KJ) Dietary Fiber 1g 4% Sugars 3g Protein 8g * The % Daily Value (DV) tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice. 3 Add to Food Diary