Periodic Motion

1. State the key elements of simple harmonic motion.

   the motion repeats on a regular cycle

   the restoring force always points toward the equilibrium position ( position where the sum of forces = 0).

   the restoring force has a linear relationship to displacement from the equilibrium position.

2. State how simple harmonic motion differs from periodic motion.
3. Define Hook's Law. F = - kx
4. State the potential energy stored in a spring in 2 ways

   mathematically: Us = 1/2kx^2

   graphically: Us = area under the force vs. displacement curve

5. State that the units of frequency are Hertz (Hz) or cycles per second.
6. State that frequency (Hz) is the reciprocal of period (seconds).
7. Calculate the period and frequency of a spring and mass system. f = 1/(2p)[k/m]^0.5
8. Explain how a spring and mass system could be used for measuring mass even in outer space.
9. Calculate the period and frequency of a pendulum. f = 1/(2p)[g/L]^0.5
10. Explain how a pendulum could be used for measuring "g".

     

Homefun (formative/summative assessment): Read sections 14.1

Formative Assessment: Physics Investigation

Follow up Questions

 

Wave Properties

11. State that energy can be transmitted great distances using mechanical waves with very little motion and no net displacement of the medium used for transmission.
12. Describe how the media moves for both transverse and longitudinal mechanical waves.
13. Give examples of transverse and longitudinal mechanical waves.

    Transverse: visible light and all forms of electromagnetic radiation are considered transvese waves

    Longitudinal: sound is considered a longitudinal wave

14. Describe how waves in the ocean can have a combination of both transverse and longitudinal properties.
15. Describe the 2 ways sin waves can be used to model waves.
16. Explain the following terms as related to the ways waves are modelled as sin waves:

    The graphs shown at right are two different representations of the same wave. speed: how fast the waves travel away from their source. This can be found by multiplying frequency by wavelength amplitude: height from horizontal axis to the peak--always a positive number. This can be measured on either graph. For the wave pictured amplitude = 2. wavelength: the length from start to finish of one wave.This can only be measured on the distance graph. For the wave pictured wavelength = 4. period: time in which one complete cycle of the wave occurs. This can only be measured on the time graph. For the wave pictured period = 2 frequency: number of cycles that occur in a unit of time.This can only be calculated from the time graph. For the wave pictured period =1/ 2.

17. State the relationship of frequency (f) to period (T). f = 1/T
18. State how speed, frequency, and period are related.

    v = l f

Homefun (formative/summative assessment) problems1, 2, 3 p. 261.

Superposition and Refraction

19. Describe how pulses superimpose.
20. Describe how waves are reflected at boundaries.

    At a fixed point on a wall a transverse wave on a spring is reflected on the opposite side.

    At a junction between springs part of the wave is reflected backwards.

21. Describe standing waves

    nodes: zero motion

    antinodes: maximum motion

22. Describe how waves are reflected. incident angle = reflected angle
23. Describe how waves are refracted.
24. Discuss how the differences in wavelength affect different parts of the electromagnetic spectrum.

    relative wave length: gamma < x-ray < ultraviolet < visible light < infrared < microwave < radio waves

    Ionizing radiation: wavelengths shorter than visible light are considered ionizing and potentially harmful.

    Transmition of information: visible light, microwave, and radio waves are all used for transmitting information. Generally the shorter the wavelength or higher the frequency the greater the amount of information that can be transmitted per unit of time.

     

Homefun (formative/summative assessment):Section Review Problems 15 to 18; page 265

Review

Formative Assessments:

1. Work review problems at the board

2. Work practice problems.

Metacognition Problem Solving Question: Can I still work the problems done in class, several hours or days later? Some amount of repetition on the exact same problems is necessary to lock in learning. It is often better to thoroughly understand a single example of a problem type than to work example after example understanding none of them completely.

Relevance: Good test preparation is essential to performance in physics class.

Homefun (formative/summative assessment): turn in on the day stapled to the back of the test.

Summative Assessment: Unit exam objectives 1-23