Question | Answer |
2.1 A man pushes a stalled car for 2 minutes. During the first 1.5 minutes the car does not moce, but for the last 0.5 minutes the man pushes harder and succeeds in getting the car to move. Is the man doing work for the entire 2 minutes? | No. |
2.1(continued) If not, does he ever succeed in doing work? Is so, when? | Yes. During the last 0.5 minutes. |
2.2 Classify each of the following as having either potential or kinetic energy, or both: (a.) A lump of coal (b.) A flash of lighting (c.) A candle flame (d.) A tornado | (a.) Potential (b.) Kinetic (c.) Kinetic (d.) Kinetic |
2.3 A chemist watches the temperature of a vat of liquid and notices that is decreases over time. What can the chemist conclude from this observation? | The temperature of the surrounding air is colder than the water. |
2.4 If a hot object is totally insulated from the outside world (totally unable to interact with anything else), will its temperature ever be able to change? | No, its temperature would reach an equilibrium constant value and stay there. |
2.5 Why should you never look to science as an ultimate source of truth? | Because the Bible is the only ultimate source of truth. |
2.6 Heat is added to two identical objects that are initially at the same temperature. If the first absorbs 100.0 cal and the second absorbs 100.0 J, which gets hotter? | The first. |
2.7 Some diet books tell you that an excellent way to lose weight is to drink ice-cold water. Why? | Because your body has to heat it in order to use it. |
2.8 Examine the heating curve on page 67 for the unknown substance. At what temperature does this substance boil? | 55 °C |
2.9 The specific heat of iron is roughly three times that of gold. Equal masses of gold and iron start out at room temperature. Heat is added to each mass at the same rate for the same amount of time. | |
2.9(continued) When it is all over, the gold's temperature increased by 900 °C. What was the temperature increase of the iron? | 300 °C |
2.10 Why should a calorimeter always be made from an insulating material? | So that very little thermal energy will be gained or lost. |