Term
| To what two quantities is work proportional? |
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Definition
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Term
| Under what condition can a force act on an object and yet do no work on that object? |
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Definition
| if the object does not move |
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Term
| Suppose you slowly, and at constant speed, lift a book weighing 12 N from the floor to a shelf 2 m above the floor. Neglect air resistance. While lifting, the net force on the book is.... |
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Definition
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Term
| Suppose you slowly, and at constant speed, lift a book weighing 12 N from the floor to a shelf 2 m above the floor. Neglect air resistance. The work done by you on the book is.... |
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Definition
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Term
| Energy could be defined as... |
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Definition
- The ability (or capacity) to do work
- work that is stored for later use
- a property of each system (isolated collection of objects) that is transferred between systems by work of one system on another
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Term
| One situation in which the law of conservation of energy is violated is.... |
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Definition
| nonsense-no violations of this law have ever been observed |
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Term
| A wrecking ball has a mass of 500kg and the highest point of the ball is 5 m above the lowest point. The ball starts from rest at the highest point. Assume that no energy is lost to air resistance and use g= 10 m/s2 for the acceleration due to gravity. What is the maximum speed of the ball? |
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Definition
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| A block of ice slides freely (without drag) down a slippery slope. The block starts from rest at the top of the slope, where it has a vertical height of 4 m above the bottom of the slope and where it has a gravitational energy of 1000 joules. At a quarter of the way down the slope (at 3/4 of the height from the bottom), the block's gravitational energy is... |
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Definition
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Term
| You slowly lift a book from the floor and put it on the table. You then lift an identical book quickly from the floor and put it on the table. Each book starts from rest and ends at rest. Which of the following is true? |
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Definition
| The power used in the second case is greater |
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Term
Which of the following statements are consistent with the Second Law of Thermodynamics?
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Definition
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Term
| The efficiency of a device is... |
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Definition
| its useful energy output divided by the total energy put into the device |
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Term
| A particular lightbulb produces 8 J of thermal energy while producing 2 J of radiant energy, and this is its entire energy output during this time. How efficient is the bulb? |
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Definition
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Term
| The efficiency of a heat engine is defined to be... |
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Definition
| work output divided by thermal energy input |
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Term
| In one cycle of operation, the thermal energy input to a particular heat engine is 200 joules and the exhaust is 80 joules. The efficiency of the engine is... |
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Definition
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Term
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Definition
| consumes 75 joules of electric energy during every second |
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Term
| Suppose tha 100 W lightbulb has an energy efficiency of 5% and is turned on for one minute (60 seconds). During this time, the visible radiant energy output of the lightbulb is.... |
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Definition
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Term
| Suppose you viewed a movie tha was running backwards. You woul see lots of odd things happening, streams would flow uphill, and so forth. If the odd "backward moving" things actually happened in nature, which principle of physics would be violated? |
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Definition
| The second law of thermodynamics |
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Term
| Which of the following statements is consistent with the Second law of Thermodynamics? |
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Definition
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Term
| When the inside of a refrigerator is cooled, does thermal energy flow from hot to cold, or is it from cold to hot? Does this happen spontaneously, or is outside assistance required? |
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Definition
| From cold to hot. Since this is against the normal flow of thermal energy , outside assistance is required. |
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Term
| This is the triboelectric series: human hair, glass, rabbit fur, cat fur, amber, balloon, polyester, plastic wrap, hard rubber. A typical plastic hairbrush be made of hard rubber. Which of these is the best explanation of the "electric hair" that can occur when some people brush their hair? |
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Definition
| Electrons are brushed from the hair onto the brush, causing the brush and hair to be changed, so thats the hairs then repel each other while the brush attracts the hairs. |
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Term
| Current is measured in amperes (A or amp). Voltage is measured in volts (V). For an electrical circuit, which of the following are correct definitions? |
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Definition
| Current: amount of electric charge that passes any point in a circuit, each second. Voltage, the amount of ElectE that a battery gives to one coulomb of electrical charge. |
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Term
| If a lightbulb has a resistance of 40 ohms and a current of 2 amps, at what voltage is it operating? |
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Definition
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Term
| Object A has an electric charge that is 10 times larger than the charge on object B. When plced near each other, how does the force by A on B compare with the force by B on A? |
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Definition
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Term
| Suppose that the electric force between two objects is 2 N and that you then halve the distance between the objects. The new force is... |
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Definition
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Term
| One difference between moving charges and stationary charges is that... |
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Definition
| moving charges exert both electric and magnetic forces, while stationary charges exert only electric forces |
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Term
| A changing magnetic field creates an electric field. This is one way of stating.... |
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Definition
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