Lecture%2020%20Work%2c%20Transportation%20and%20Electricity-posted

# Lecture%2020%20Work%2c%20Transportation%20and%20Electricity-posted

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1 Today Worksheet 13 continued More on transportation Electricity Announcements: Please bring your laptops to the next two lectures. Practice final exams will be posted next week. Solutions will be available a week later.

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2 Worksheet 13, Q5 Calculate the total fuel consumption of a Toyota Corolla over a distance of 100 km. The typical efficiency of a car engine is e = 0.20. The available chemical energy from gasoline is 35 MJ per litre. (Work done by rolling friction and air drag = 40 MJ.) A. Less than 3 L B. 4 – 5 L C. 5 – 6 L D. 6 – 7 L E. More than 7 L The Corolla is rated at 6.2 L/100 km (highway) or 38 mpg.
3 Worksheet 13, Q6 So far we have neglected changes in speed. Estimate how much gasoline is used to accelerate a 1200 kg car from 0 - 80 km/h. Neglect other effects such as friction and air drag. A. 8 mL B. 21 mL C. 42 mL D. 85 mL E. > 100 mL (1 Cup = 237 mL)

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Extra Problem Cycling at slow speeds requires relatively little power when you travel on level ground. At what speed does the air drag become equal to the rolling resistance? • Bicycle tire on road: r = 0.005. Hint: You have to assume a reasonable mass and frontal surface area for the cyclist. v
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## This note was uploaded on 05/19/2011 for the course PHYS PHYS 100 taught by Professor Lioudmila during the Winter '10 term at The University of British Columbia.

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Lecture%2020%20Work%2c%20Transportation%20and%20Electricity-posted

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