4-22-09

Today in Mr. Mannings first period class we had three objectives. They were as follows.

__**Today's Objectives**__: Graded Daily Question More on Inference Superposition Principle
 * Handouts** included Pg 12 and 14, Ch 20 Wave Superposition

a) The bird at the right watches the waves. If the position of a wave between two crests passes the pole each second, what is the speed of the wave? What is the period? =1 Hz x 1m= 1m/s T= 1/f = 1/1 = 1s b) If the distance between crests in the above question were 1.5m apart, and 2 crests pass the pole each second, what would be the speed of the wave? What would be the period? =1Hz x 1.5 m= 1.5 m/s =1/f= 1/1 = 1s
 * __Daily Question__** [[file:DQ.bmp]]
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__**Inference on pg. 11**__
 * Constructive Inference-** This occurs when two waves both positive displacements (up) or negative displacements (down) are traveling in opposite directions and meet. A much greater amplitude is created that is the sum of both crests or troughs.
 * Destructive Inference-** This occurs when two waves with opposite displacements (one negative, one positive) travel opposite directions and meet. In this case, the amplitude is still the sum of both amplitudes but somewhat cancel each other out. If both opposite amplitudes are the same they will cancel out.
 * Superstition Principle-** This is the rule that states the amplitude of the resulting pulse is the sum of the displacements of the individual pulses.

After explaining more in detail, Mr. Manning instructed us to complete pgs 12 - 14 where we were to draw the waves each second. They soon interfere and we are to figure out the composite wave.