Phys 150 Lecture 31 Please sit together in pairs: –Onyema and Honglu –Alejandra and Matt...

Phys 150 Lecture 3 1

• Please sit together in pairs:

– Onyema and Honglu– Alejandra and Matt– Chris and Lin– Ryan and Anwen– John F. and Mengyue– Walter and Melissa– Max and Zhongyun– Amanda and Kaijun– Pauline and Erich– Jake and Irfan– John W. and Jason – Jennifer and Jiayuan

– Alexandra and Erica– David and Dian– Abigael and Michael

Phys 150 Lecture 4 2

Announcements

• Homework 2 is due on Sunday at midnight.

• Quiz on Chapter 2 on Tuesday.• Quiz 1 solution is available on web page.• Homework 1 solution is available on web

page• Suggestion: Do the Homework 3

multiple-choice questions before coming to class on Tuesday. Also look at questions at end of Chapter 2.

Phys 150 Lecture 4 3

Announcements

• I will drop your lowest homework and your lowest quiz scores at the end of the semester.

Phys 150 Lecture 4 4

Phys 150 Lecture 3 5

Cost of energy

• Coal ($46/ton, IL) 0.8¢ ----• Natural gas ($3.50/MMBtu) 1.2¢

3.2¢• Gasoline ($3.29/gal) 10¢ ----• Electricity 10¢ 10¢

• Coal and natural gas are about 33% efficient for generating electricity (up to 60% for natural gas)

• Conventional cars have an efficiency of about 20%• Electric cars have an efficiency of about 80%• Coal and natural gas are very cheap (and

abundant, for now)

per kWh

per kWh from Ameren IL

Phys 150 Lecture 3 6

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Phys 150 Lecture 4 9

12-Apr-2011 Phys 150 Lecture 22 10

Hydraulic fracturing + horizontal drilling

12-Apr-2011 Phys 150 Lecture 22 11

i>clicker question

The fossil fuel that produces the most carbon dioxide per kWh of energy is

A. natural gas B. oil

C. coal D. They’re all about the same.

12-Apr-2011 Phys 150 Lecture 22 12

i>clicker question

The fossil fuel that produces the most carbon dioxide per kWh of energy is

A. natural gas – CH4 1/2

B. oil – hydrocarbons 3/4

C. coal – carbon 1D. They’re all about the same.

H ends up as H2O

C ends up as CO2

12-Apr-2011 Phys 150 Lecture 22 13

i>clicker question

The fuel cost to drive an electric car one mile compared to a gasoline car is about

A. the same B. 1/2 C. 1/4D. 1/8

12-Apr-2011 Phys 150 Lecture 22 14

i>clicker question

The fuel cost to drive an electric car one mile compared to a gasoline car is about

A. the same B. 1/2 C. 1/4D. 1/8

Gasoline: $3.50/gallon 10 cents/kWh Same price as electricity

Efficiency: 20% for gasoline car, 80% for electric car

Gasoline Vehicle

Electric Vehicle (EV)

Plug-in Hybrid Electric Vehicle (PHEV)