71. An object, if moving rhythmically when stimulated in a natural period, is said to ____.

1. vibrate
2. resonate
3. swing
4. oscillate

72. The distance a swing moves from its resting position is called its ____.

1. revolution
2. movement
3. frequency
4. amplitude

73. A tachometer is an instrument that uses resonance to determine ____.

1. the speed of a motor in revolutions
2. the frequency at which a motor vibrates
3. the amplitude of a fan engine that oscillates
4. the changes in a dial within a car engine

74. An annoying vibration can be caused at the natural resonance of the car's engine mount ____.

1. if the engine moves too fast
2. if the engine's amplitude increases
3. if a tire gets out of balance
4. if a damage occurs in the engine

75. In which of the following cases is it useful to consider the relationship between the length of an oscillating object and its natural period?

1. Adjusting the speed of a car.
2. Adjusting a clock pendulum.
3. Adjusting tire balance.
4. Adjusting engine mounts.

(Reference keys.)