What type of energy would each of the following be?
A barrel of oil
The sun beating down a solar panel
A piston moving in a car engine - answerA barrel of oil - Chemical energy
The sun beating down a solar panel - Thermal energy
A piston moving in a car engine - Mechanical energy
A steel rod is initially very cold. If it is placed close to a fire, what happens?
A) The steel rod heats up.
B) The fire goes out.
C) Nothing happens. - answerA) The steel rod heats up.
Which do you think is more efficient?
A) A jet engine that produces 70 units of work from 100 units of energy.
B) A vehicle that produces 50 units of work from 100 units of energy.
C) A water mill that produces 10 units of work from 100 units of energy. - answerA) A jet
engine that produces 70 units of work from 100 units of energy.
There are a little more than 7.5 billion people on the planet today, but 2.5 billion people
are using most of the energy. The UN projects that human population will stabilize
around 10 billion people by the year 2100 - an addition of 2.5 billion more people. How
much would energy use increase by if 10 billion people in 2100 are using the amount of
energy 2.5 billion people are using today?
A) 4x
B) 2x
C) 1x
D) 3x - answerA) 4x
Through a combination of fertility rate and decreased poverty levels, a population's
energy use is growing exponentially 1% per year. How many years until the energy use
doubles? - answer69.3 years
,t= 0.693/rate = 0.693/0.01 = 69.3 years
What energy growth rate per year would increase world energy use by 400% (2
doubling periods) in 80 years? - answer1.7 per year
t=0.693/rate --> rate=0.693/time
rate= 0.693/40 = 1.7% per year
A wind turbine costs $10 million to construct and generates $1 million worth of electricity
per year. When has the wind turbine paid for itself (what is the pay-back period)? -
answer10 years
What do you think "embedded" energy is? - answerThe energy that goes into making
something.
What is the biggest use of energy in a home? - answerheating and air conditioning
Kevin lives next to a power plant that burns coal. He wants to be more green, so he
buys an electric car that he can plug into his home electricity. What is powering Kevin's
car? - answercoal
Which has more kinetic energy?
A) An oil tanker moored at a terminal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - answerD) A car moving
at 120 mph across the Bonneville Salt Flats.
Which series goes from least energetic to most? - answerRadio < infrared < ultraviolet <
x-rays
Which has more potential energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - answerB) A cubic mile of
water (a lake) behind a 300 ft tall dam.
Which has more nuclear energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
, D) A car moving at 120 mph across the Bonneville Salt Flats. - answerC) An atomic
bomb in a silo in North Dakota.
Which has more chemical energy?
A) An oil tanker moored at a terminal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - answerA) An oil tanker
moored at a terminal.
The hot coffee heats the mug which heats my hands which are holding the mug. What
method of heat transfer is it? - answerConduction
What transformation occurs in the Sun? - answerNuclear to radiation
What transformation occurs in a computer? - answerElectrical to light/sound
What transformation occurs in a lawn mower? - answerChemical to kinetic/mechanical
A power plant consumes 100 MJ of Energy, of which only 24 MJ are wasted heat. What
is the efficiency? - answer0.76
A power plant converts 100 kJ of coal into 30 kJ of electrical energy. What is the
efficiency? - answer30%
Efficiency = Eout/Etotal
= 30/100 = 30%
Your home converts 30 kJ of electrical energy into 15 kJ of useful energy (heat, electric)
and 15 kJ of wasted energy. What is your home's efficiency? - answer50%
Efficiency = Eout/Etotal
= 15/30 = 50%
It took 100 kJ of coal to produce the 15 kJ of useful energy in your home. What is the
total efficiency? - answer15%
Efficiency = Eout/Etotal
= 15/100 = 15%
The Penn State natural gas plant produces 7 MW of power. If it runs at 70% efficiency
and has 7MW Power Out, what is the rate of energy input? - answer10 MW
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