Act1_sol

# Act1_sol - 6/13/05 Activity 1 Solutions: Introduction to...

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6/13/05 1 Activity 1 Solutions: Introduction to Physics 104 1.1 Review of Ratio Reasoning and Efficiency Your instructor will review ratios and the efficiency of energy processes. 1) Efficiency of light bulbs Compare the relative efficiencies of an incandescent bulb and a compact fluorescent bulb. a) Use a wattmeter to measure the power required by an incandescent bulb. ___________ b) Measure the power required by a compact fluorescent bulb. ___________ c) Measurements have shown that each of these bulbs produce 3 watts of visible light. Calculate the efficiency of the incandescent bulb. Efficiency = 3 watts / # of watts measured in part 1) d) Calculate the efficiency of the compact fluorescent bulb. Efficiency = 3 watts / # of watts measured in part 2) e) How do the efficiencies of the bulbs compare? The compact fluorescent is much more efficient. f) Group Discussion Question: Why is the compact fluorescent bulb so much more efficient than the incandescent bulb? 2) Generating electricity with the exercise bicycle a) If five 50-watt bulbs are lit, how many kilowatts of electricity are generated? 5 bulbs x 50 watts = 250 watts x 1 kW = 0.25 kW bulb 1,000 watts b) If you ride the bicycle and generate this much electricity for 8 hours, how many kilowatt hours of electricity have you generated? 0.25 kW x 8 h = 2 kWh c) If you sold the electricity you generated for \$0.10/kWh, how much money would you receive for it? If electricity costs \$0.10/ kWh, you would make only \$0.10 x 2 kWh = \$0.20 k W h 1.2 Linear and Exponential Growth Rates and Exponential Decay Your instructor will discuss linear and exponential growth and exponential decay. 3) Illustrating exponential decay Roll the 20 dice in the plastic cup onto your table and remove any dice that land with a “1” showing. Repeat for 20 throws, each time removing any dice showing a “1.” After each roll, record below the number of dice left after you remove the dice showing a “1.” When each table has completed 20 throws, we will combine the data for all groups.

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6/13/05 2 Roll Dice Left Dice Left Roll Dice Left Dice Left Your table All tables Your table All tables 1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19 10 20 a) On the graph, using the totals for all groups, plot the number of dice left versus the number of rolls of the dice. What type of change does this graph line represent?
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## This note was uploaded on 06/11/2011 for the course PHYSICS 104 taught by Professor Staff during the Winter '11 term at Ohio State.

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Act1_sol - 6/13/05 Activity 1 Solutions: Introduction to...

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