Phy 101 Practice Exam #2

1.). You place your hand on a window on a cold winter's day and your hand becomes cold. This is an example of ______. a. thermal conduction b. thermal convection c. thermal radiation d. thermal expansion e. none of the above

2.) If a 0.08 kg hot wheel car starts at the top of a 2 meter hill, what is its speed at the top of the next 0.3 meter hill? Neglect track friction.

a. 33,3 m/s d. 4.08 m/s b. 2.42 m/s e. 5.77 m/s c. 16.6 m/s

3.) Suggestions made in class to lower the concentration of CO2 in the atmosphere and slow down the greenhouse effect include all but one of the following. Choose the INCORRECT suggestion.

a. Develop alternate energy sources. b. Use cars less often and find methods of cleaning the exhaust. c. Stop cutting the rainforests and other forests. d. Use alternate sources for making paper such as hemp. e. Change the wavelength of the radiation of the earth making it longer.

Hill E Hill A Hill C

Valley B Valley D

4.) Choose the best statement below about the roller coaster. NEGLECT FRICTIONAL LOSSES.

a. The cart will be going faster on Hill E than Hill C. b. The cart will be going slower in Valley B than Valley D. c. The cart will not be able to get over Hill E. d. The cart will be going slower in Valley B than on Hill C. e. The cart would not be able to make it over Hill C. 5.) The amount of heat required to raise 4 kg of gasoline from 24oC to 59oC is ______. The specific heat capacity of gasoline is c = 0.5 Cal /kgoC.

a. 17.5 Cal. b. 35 Cal. c. 70 Cal. d. 140 Cal. e. 105 Cal.

Using the graph above, answer the following two questions.

6.) About what percent of the US energy consumption is based on fossil fuels today (2006)? a. ~84% d. ~60% b. ~ 90 % e. ~ 40% c. ~ 47%

7.) If we decided to double our nuclear power production in the next 24 years, how would that compare to the projections? a. The projected amount of ~4 quadrillion BTUs, would be equal to the use now. b. The projected amount is ~9 quadrillion BTUs in 24 years, while doubling would put us at 16 quadrillion BTUs. c. The doubled power would also increase the amount of hydroelectric power. d. Doubling our nuclear power production is impossible with today’s technology. e. Doubling our nuclear power production could allow us to quit using natural gas in 24 years. 8.) While the last 100 years have only experienced an increase in temperature of about 0.5oC or 0.7oF, the modest global temperature ______was responsible for the last ice age (10,000 years ago). a. increase of 3oF b. drop of 9oF c. increase of 10oF d. drop of 30oF e. drop of 50oF

9 .) How much work must be done to accelerate a 5000 kg boat from a speed of 0.5 m/s to 3.5 m/s? a. 22500 J b. 45000 J c. 60000 J d. 12000 J e. 30000J

10.) The walls in a building are made of concrete with sets of double windows in them. If several windows are put together along each wall, how much space is needed between each window (side to side) to allow for thermal expansion? The weather varies annually from -10oC to +42oC and windows are 13 m wide. [(glass) = 2.3x10-5(oC)-1] a. 3.2 cm b. 0.8 cm c. 1.6 cm d. 0.000016 m e. 0.032 m

11.) Which of the following are likely results of a warming planet? a. A,B c. B,C e. A,B,D,E b. A,B, C d. C,E

A. Change in weather patterns B. Increase in insect carrying diseases C. Increase in polar ice with decrease in ice around Iceland D. Loss of animal species as habitat changes too quickly E. Rising costs of fossil fuels as they are depleted. From the graph above which relates Ocean Heat Content (in JOULES – energy units !!!) to year, answer this 2 questions.

12.) The heat content in the ocean around the years ______is used as the “normal” reading (or zero line) for scientists. a. 1955-2005 b. 1970 – 1975 c. 1975-1980 d. 1995-2000 e. 2000-2005

13.) In 1995, the most heat content was found ______. a. in the 0 – 3000 m layer b. to be ~ 12 x 1010 J c. in the 0 – 300 m layer d. in the 0 – 700 m layer e. to be ~ 4 x 1010 J Point A: Ball Released from Dog's m outh

Point B: Ball falls part of the way down

Point D: Other side of ditch

Point C: Ball just before hits ground

Answer the following question using the picture above as a reference.

14.) Choose the CORRECT statement about the above picture. a. The potential energy of the ball at point A is greater than the kinetic energy of the ball at point C. b. The kinetic energy at point C is less than the kinetic energy at point B. c. The potential energy at point B is greater than the kinetic energy at point C. d. The potential energy at point B is greater than the kinetic energy at point B. e. The potential energy at point B is the same as the potential energy at point C.