Deck 13: Energy and Power

Question 1

In the U.S.customary system of units, the unit for kinetic energy is

A)lbf.ft
B)lbf.ft/s
C)slugs.ft
D)horsepower

Answer 1

A

Question 2

What is the SI unit for gravitational potential energy?

A)Newtons
B)Watts
C)Kelvins
D)Joules

Answer 2

D

Question 3

An object having a mass m and moving with a speed V has a kinetic energy, which is equal to

A)mV
B)mV2
C)½ mV2
D)½ mV

Answer 3

C

Question 4

Which of the following requires the most work done by the brakes of a car?

A)slowing down from to

B)stopping from
C)equal amounts of work for both

Question 5

A ping pong ball and a bowling ball are moving with the same momentum.Which has the greater kinetic energy?

A)The ping pong ball
B)The bowling ball

Question 6

How much kinetic energy does a 200 g soccer ball have while moving at toward your opponents' goal?

A)4 Joules
B)40 Joules
C)80 Joules
D)8 Joules

Question 7

Mechanical work is performed when a force moves an object through a distance.

Question 8

What is the SI unit for elastic energy?

A)Newtons
B)Watts
C)Kelvins
D)Joules

Question 9

If you were to push a lawn mower with a constant horizontal force of 20 N.How much work do you do while pushing the lawn mower a total distance of 100 m on level ground?

Question 10

Calculate the energy required to lift an elevator and its occupants with a mass of 1000 kg through a vertical distance of 5 m.

A)5000 J
B)49000 J
C)25000 J
D)2500 J

Question 11

What is the SI unit for work?

A)Newtons
B)Watts
C)Kelvins
D)Joules

Question 12

In the following equation, what does the k stand for? elastic energy

A)kinetic energy
B)spring constant
C)modulus of elasticity
D)momentum

Question 13

Work is found by multiplying force by what other physical quantity?

A)distance
B)mass
C)power
D)time

Question 14

When work is done on or against an object, it changes the kinetic energy of the object

Question 15

A stone is dropped from a bridge and allowed to free-fall downward.As it falls a certain distance its gravitational potential energy decreases by1000 J.By how much does the stone's kinetic energy increase? (Neglect air resistance).

A)100 J
B)500 J
C)1000 J
D)2000 J

Question 16

The change in gravitational potential energy is found by multiplying an object's change in elevation by its

A)mass
B)weight
C)density
D)height

Question 17

Energy is a fundamental dimension.

Question 18

Which produces the greater change in kinetic energy (assume that all of the work goes into kinetic energy)?

A)exerting a 10 N horizontal force through a distance of 5 m
B)exerting a horizontal force of 20 N through a distance of 2 m
C)exerting a 30 N horizontal force through a distance of 1.5 m
D)exerting a horizontal force of 40 N through a distance of 1m

Question 19

Power is a derived dimension.

Question 20

What is the SI unit for gravitational potential energy?

A)Newtons
B)Watts
C)Kelvins
D)Joules

Question 21

One Btu is

A)nearly equal to 1000 J
B)much smaller than 1000 J
C)much greater than 1000 J
D)none of the above

Question 22

The U.S.natural gas transportation network consists of 2.4 million kilometers of mainline and secondary pipelines.

Question 23

In the following equation, what does the x stand for? elastic energy

A)deflection of a spring from its unstretched position
B)original length of an unstretched spring
C)spring force
D)total length of a stretched spring

Question 24

Thermal energy transfer occurs whenever there exists a temperature difference within an object, or whenever there is a temperature difference between two bodies, or a temperature difference between a body and its surroundings.

Question 25

A direct passive solar system uses large glass areas on the south wall of a building and a thermal mass to collect the solar energy.

Question 26

Thermal energy transfer is called

A)temperature difference
B)heat difference
C)temperature flux
D)heat

Question 27

The SI unit for power is

A)watts
B)joules
C)newtons
D)horsepower

Question 28

What are the SI units for heat?

A)Kelvins
B)Celsius
C)Joules
D)Watts

Question 29

In the absence if heat transfer and no work, conservation of mechanical energy states that the total mechanical energy of a system is

A)increasing
B)constant
C)decreasing
D)none of the above

Question 30

One horsepower represents the power required

A)to lift an object weighing 978 N, a distance of 0.762 m in 1 second.
B)to lift an object weighting 489 N a distance of 1.676 m in 1 second.
C)to lift an object weighting 244.5 N a distance of 3.353 m in 1 second.
D)all of the above

Question 31

The time rate of doing work is called

A)energy
B)power
C)force
D)momentum

Question 32

Power can be described as

A)how hard you push.
B)how fast you push.
C)how far you push.
D)how long you push.

Question 33

A common unit used in the United States in air-conditioning and refrigeration systems is ton of refrigeration or cooling.One ton of refrigeration represents the capacity of a refrigeration system to freeze

A)1000 lbm of liquid water at 0°C into 0°C ice in one hour.
B)2000 lbm of liquid water at 0°C into 0°C ice in 24 hours.
C)1000 lbm of liquid water at 0°C into 0°C ice in 24 hours.
D)2000 lbm of liquid water at 0°C into 0°C ice in one hour.

Question 34

Power is found by dividing work by what other physical quantity?

A)distance
B)mass
C)force
D)time

Question 35

The law that simply states that energy is conserved is

A)the 0th law of thermodynamics.
B)the 1st law of thermodynamics.
C)the 2nd law of thermodynamics.
D)the 3rd law of thermodynamics.

Question 36

In general, efficiency is defined as

A)actual output divided by required input.
B)required input divided by actual output.
C)actual output multiplied by required input.
D)actual output minus required input.

Question 37

A team is more powerful than an individual because

A)the team can do more work than the individual in the same amount of time.
B)the team can do the same amount of work as the individual, but in less time.
C)the team can do more work than the individual in less time.
D)All of the above.

Question 38

Two types of wind turbines are used to extract the energy from the wind, a vertical axis turbine and a horizontal axis turbine.

Question 39

Solar energy starts with the sun at an average distance of 93 million miles from earth.The sun is a nuclear fusion reactor, with its surface temperature at approximately 10,000° F (5500° C).

Question 40

A photovoltaic system converts light energy directly into heat.

Question 41

Ethanol is an alcohol-based fuel that is made from the sugars found in corn and barley.Other sources, such as rice, sugar cane, and potato skins, are also used to produce ethanol.