Chapter 9 review


    Vocabulary
    Match each word to the sentence where it best fits.
      Section 9.1

      elastic potential energy gravitational potential energy
      joule (J) kinetic energy
      mechanical energy potential energy
      reference frame spring constant
      work 
      1. _____ is done on an object when a force acts on the object as it moves through a distance.
      2. A/An _____ is the amount of energy that is sufficient to produce a force of 1 N that acts for 1 m.
      3. Global positioning satellites provide a/an ________ from which you can determine your position on the Earth and the current time.
      4. A compressed spring has ________ equal to the work that the spring could do if it expanded again.
      5. The _______ goes up by a factor of 4 if the speed increases by a factor of 2.
      6. The ________ is a quantity that indicates the strength of the restoring force exerted by an elastic material when it is stretched.
      7. Water at the top of a dam has ________ as a result of its height above the bottom of the dam.
      8. Energy due to motion and energy due to position (such as height) are both categorized as kinds of _______.
      Section 9.2

      ampere (A) electric current
      horsepower (hp) intensity
      light power
      radiant energy renewable energy
      volt (V) watt (W)
      1. ________ is the kind of energy that is carried by electromagnetic waves.
      2. Seven-hundred and forty-six watts is equal to one _________.
      3. _________ is a form of energy that can be replenished as rapidly as it is used.
      1. An indicator of electric potential is the ________.
      2. A/An ________ is the SI unit for electric current.
      3. The flow of charged particles is called ________.
      4. The _______ of light describes how many watts of power fall cross one square meter of area.
      5. An energy flow of one joule per second is called one ________.
      6. The rate at which work is done is called ______.
      Conceptual questions
        Section 9.1
        1. How much work does it take to hold a dumbbell motionless over your head for 10 s?
        2. What physical quantity is measured by a spring scale?
        3. String and nylon thread will stretch when pulled with a moderate force, but only a small amount. If you apply the same force to a spring and it stretches much further than the string and thread, how do the spring constants of the string and thread compare to the spring?
        4. How do you account for the mass of the hook when using a hooked lab mass?
        5. Two apartment mates are arguing over the potential energy of a 10 kg TV that hangs on the wall. The first person claims that the television is 2 m from the floor so its potential energy is 10 kg × 9.8 N/kg × 2 m = 196 J. The other claims that since they are on the second floor, the TV is 12 m above the ground so the potential energy is 10 kg × ×9.8 N/kg × 12 m =1,176 J. Who is right or are they both right? Explain.
        6. Easy For a classroom investigation, a teacher hangs a heavy bowling ball by a rope from the ceiling so that the ball hangs at a height just a little lower than the teacher’s nose. The teacher faces the ball, steps backward a few steps and draws the ball toward her until it just touches the tip of her nose. She then asks her class if she will remain uninjured when she releases the bowling ball—knowing it will swing away then reverse and swing back toward her nose again. How should you answer her?
        7. Easy What happens to the energy “lost” to friction?
        8. Easy Compare the change in potential energy between a ball that falls from 10 m to 5 m in height and another ball of the same mass that falls from 7 m to 2 m in height.

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