Question 1

A 100 W lightbulb has an energy efficiency of 5%. It is turned on for one minute. Its total energy output during this minute is

Accepted Answer

A)   5700 J.
B)   300 J.
C)   6000 J.
D)   impossible to determine because we don't know the voltage.
E)   impossible to determine because we don't know the power.

Question 2

Which of the following energy transformations represents the operation of a wind turbine [a device that uses the wind as an energy resource]?

Accepted Answer

A)   Thermal E ·Electric E
B)   Kin E ·Electric E
C)   Grav E ·Electric E
D)   Electric E ·Kin E

Question 3

The "energy efficiency" of a device is

Accepted Answer

A)   the total energy put into the device divided by its useful energy output.
B)   its useful energy output divided by the total energy put into the device.
C)   its total energy output divided by the total energy put into the device.
D)   its thermal energy output divided by the total energy put into the device.
E)   the total energy put into the device divided by its thermal energy output.

Question 4

Which of these energy transformations best describes the overall operation of a hydroelectric power plant?

Accepted Answer

A)   grav E ·therm E
B)   electromag E ·grav E
C)   thermal E ·electromag E
D)   grav E ·electromag E
E)   chem E ·electromag E

Question 5

The sub- atomic particle known as the "neutrino" was originally hypothesized

Accepted Answer

A)   in order to preserve the law of conservation of energy in a certain type of nuclear process.
B)   because it was thought that thermal energy (or heat)  is actually a form of energy.
C)   in order to preserve Newton's laws in a certain type of nuclear process.
D)   in order to preserve conservation of electric charge in a certain type of nuclear process.
E)   because it was thought that radiant energy is actually a form of energy.

Question 6

A 10 kg meteor moves through outer space, far from all gravitational influences. How much work is done on the meteor during a 5 m segment of its path?

Accepted Answer

A)   none
B)   20 J
C)   500 J
D)   2 J
E)   50 J

Question 7

When water evaporates from the ocean and rises into the atmosphere, the energy transformation is

Accepted Answer

A)   gravitational energy ·electromagnetic energy.
B)   kinetic energy ·thermal energy.
C)   chemical energy ·gravitational energy.
D)   chemical energy ·thermal energy.
E)   radiant energy ·gravitational energy.

Question 8

Early human culture, involving villages and a sense of history, could best be described as a(n)

Accepted Answer

A)   industrial culture.
B)   hunting culture.
C)   agri- culture.
D)   scientific culture.
E)   migratory culture.

Question 9

A gas can containing a gallon of gasoline is stored in a basement. This gasoline contains

Accepted Answer

A)   energy.
B)   both work and energy.
C)   both energy and power.
D)   work.
E)   neither work nor energy.

Question 10

What is the main energy transformation (input and useful output)  for a person speeding up while riding a bicycle?

Accepted Answer

A)   elastic E ·kinetic E
B)   chemical E ·kinetic E
C)   thermal E ·kinetic E
D)   chemical E ·elastic E
E)   kinetic E ·chemical E

Question 11

Which of the following measures would help reduce the need for new electric power plants?

Accepted Answer

A)   Energy storage methods at electric power plants.
B)   More energy- efficient use of electricity.
C)   "Time- of- day"pricing that charges more for electricity at the "peak" times.
D)   All three of the above measures would help.
E)   Both measures A and C would help, but not B.

Question 12

The figure above shows a marble rolling freely back and forth along a curved track. The track is positioned vertically. At position A its gravitational energy is

Accepted Answer

A)   less than its gravitational energy at B.
B)   greater than its gravitational energy at B.
C)   the same as its gravitational energy at B.

Question 13

In order to quadruple an object's kinetic energy, we must

Accepted Answer

A)   stretch it twice as far.
B)   quadruple its height.
C)   double its height
D)   double its speed.
E)   quadruple its speed.

Question 14

A physics professor pushes against a stationary wall, "working" up a sweat. Is he doing any actual physical work on the wall?

Accepted Answer

A)   No-- it's a law of nature that physics profs never do any actual work.
B)   No, because the wall is not moving.
C)   Yes, because his arm muscles are moving other muscles through a distance.
D)   Yes, because he is exerting a force against the wall during a period of time.
E)   No, because the force by his hands against the wall is balanced by the force by the wall pushing back.

Question 15

The kilowatt is a measure of

Accepted Answer

A)   energy.
B)   power.
C)   force.
D)   speed.
E)   sex appeal.

Question 16

The amount of energy consumed in one day in your home town could be measured in units of

Accepted Answer

A)   joules.
B)   either watts or joules.
C)   horsepower.
D)   watts.
E)   newtons.

Question 17

Which of the following is a unit of energy?

Accepted Answer

A)   newton
B)   newton/second
C)   watt
D)   Calorie
E)   None of the above.

Question 18

A 75- watt lightbulb

Accepted Answer

A)   consumes 75 joules of electric energy during every second.
B)   creates 75 joules of thermal energy during every second.
C)   creates 75 joules of radiant energy during every second.
D)   creates a total of 75 joules of radiant energy during the entire lifetime of the bulb.
E)   consumes a total of 75 joules of electric energy during the entire lifetime of the bulb.

Question 19

One car is traveling twice as fast as a second car. How much more work can the first car do. compared to the second car, in smashing into a brick wall?

Accepted Answer

A)   three times as much
B)   the same amount as the second car
C)   twice as much
D)   four times as much
E)   All of the above.

Question 20

Thermal energy can be described as

Accepted Answer

A)   macroscopic kinetic energy.
B)   microscopic kinetic energy.
C)   Both of the above.
D)   None of the above.

Exam 6: Conservation of Energy: You Cant Get Ahead

One car is traveling twice as fast as a second car. How much more work can the first car do. compared to the second car, in smashing into a brick wall?

Correct AnswerverifiedShow Answer

A 75- watt lightbulb

Correct AnswerverifiedShow Answer

The figure above shows a marble rolling freely back and forth along a curved track. The track is positioned vertically. At position A its gravitational energy is

Correct AnswerverifiedShow Answer

Which of the following measures would help reduce the need for new electric power plants?

Correct AnswerverifiedShow Answer

A physics professor pushes against a stationary wall, "working" up a sweat. Is he doing any actual physical work on the wall?

Correct AnswerverifiedShow Answer

The amount of energy consumed in one day in your home town could be measured in units of

Correct AnswerverifiedShow Answer

A gas can containing a gallon of gasoline is stored in a basement. This gasoline contains

Correct AnswerverifiedShow Answer

Early human culture, involving villages and a sense of history, could best be described as a(n)

Correct AnswerverifiedShow Answer

Which of the following is a unit of energy?

Correct AnswerverifiedShow Answer

Which of these energy transformations best describes the overall operation of a hydroelectric power plant?

Correct AnswerverifiedShow Answer

The kilowatt is a measure of

Correct AnswerverifiedShow Answer

What is the main energy transformation (input and useful output) for a person speeding up while riding a bicycle?

Correct AnswerverifiedShow Answer

A 100 W lightbulb has an energy efficiency of 5%. It is turned on for one minute. Its total energy output during this minute is

Correct AnswerverifiedShow Answer

Which of the following energy transformations represents the operation of a wind turbine [a device that uses the wind as an energy resource]?

Correct AnswerverifiedShow Answer

In order to quadruple an object's kinetic energy, we must

Correct AnswerverifiedShow Answer

A 10 kg meteor moves through outer space, far from all gravitational influences. How much work is done on the meteor during a 5 m segment of its path?

Correct AnswerverifiedShow Answer

The sub- atomic particle known as the "neutrino" was originally hypothesized

Correct AnswerverifiedShow Answer

Thermal energy can be described as

Correct AnswerverifiedShow Answer

The "energy efficiency" of a device is

Correct AnswerverifiedShow Answer

When water evaporates from the ocean and rises into the atmosphere, the energy transformation is

Correct AnswerverifiedShow Answer

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