Midterm 1

# Midterm 1 - Ther Pot Tot h = 0 4 According to your textbook...

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1. Which is not an energy unit? (Choose all that apply, 1 mark) A) Cal B) kcal C) kWh D) Btu E) MJ/day 2. Imagine a cold winter morning with a temperature of -5 0 C outside. You're not planning on being in the house during the day. If you turned the thermostat down from 20 0 C to 15 0 C, approximately what percentage of your heating energy do you save? (1 mark) A. 10% B. 20% C. 25% D. 30% E. negligible (below 1%) F. None of the above/something else. 3) Recently, two professional BMX riders performed stunts at UBC with their bicycles. Many of these stunts involve riding up a ramp and getting air-borne (see picture). According to the energy bar diagram, where is the rider? (This is not necessarily the position shown in the picture.) The potential energy is zero at h = 0 and the height scale is indicated. (1 mark) A) At the bottom of the ramp. B) At the top of the ramp. C) Going up the ramp. D) In mid-air going up or down. E) In mid-air at the highest point. h = h max h = ½ h max Kin.

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Unformatted text preview: Ther Pot. Tot. h = 0 4. According to your textbook, the total metabolic power of a 68 kg person during a fast run at 15 km/h is 1150 W. If your roommate brings home a box of Timbits and you eat 8 of them, how long do you need to run for in order to burn off the extra calories (assuming the same metabolic power)? Three Timbits have approximately 200 kcal. (3 marks) 5. Your family has a small wooden cabin in Northern B.C. The cabin is shaped like a box and its dimensions are 3.5 m x 2.5 m x 2.0 m (length, width, height, respectively). The walls and the ceiling are 15 cm thick and one of the walls has a small single-pane window that is 60 cm x 40 cm in size. You and two friends want to stay in the cabin in late fall when the outside temperature is typically 5 C. You have to decide whether a small 500 W space heater will be enough to keep you comfortable or whether you have to buy a bigger one. Be sure to explicitly show your model and assumptions. (4 marks)...
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Midterm 1 - Ther Pot Tot h = 0 4 According to your textbook...

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