1. In a standing wave, the medium at the tip of a loop is
a) showing destructive interference
b) not moving
c) at the original amplitude of the wave
d) showing constructive interference
my answer: b
2. If a motorcycle is travelling toward an observer the frequency the observer hears is ___ the actual sound made by the motorcycle
a) greater than
b) lower than
c) smaller than
d) the same as
my answer: a
1)b
2) a, because closer he gets louder it sounds
thanks a lot!
1) b
2) a
1. Well, in a standing wave, the medium at the tip of a loop is actually showing constructive interference! It's like they're having a party and getting together to create a big wave of fun!
2. Ahhh, the sound of a motorcycle approaching. If you hear the frequency to be greater than the actual sound made by the motorcycle, then you might want to check your ears. Or maybe the motorcycle just upgraded its sound system to give you the full surround sound experience! So, the answer is option A, greater than! Party on!
To answer the first question, it is important to understand the concept of standing waves. Standing waves are formed when two waves with the same frequency and amplitude travel in opposite directions and interfere with each other. The result is a pattern of nodes (points of no displacement) and antinodes (points of maximum displacement) that appear to be standing still.
In a standing wave, the medium at the tip of a loop refers to the location where the maximum displacement occurs. This point is known as an antinode. Here, the medium is experiencing the maximum displacement and is not at rest. Hence, the correct answer is not b) not moving.
To answer the second question, we need to consider the phenomenon known as the Doppler effect. The Doppler effect describes the change in frequency or pitch of a sound wave due to the relative motion between the source of the sound and the observer.
When a motorcycle is traveling towards an observer, the sound waves it produces are compressed or "squeezed" due to the motion towards the observer. This compression causes an increase in the observed frequency of the sound wave. Therefore, the answer is a) greater than, as the frequency heard by the observer is greater than the actual frequency produced by the motorcycle.
1. B, i agree with you
2. smaller than i think (b). the question is badly phrased.you hear a higher frequency (higher pitch) but an increased pitch is a shorter (smaller) wavelength. so technically the frequency is SHORTER, smaller would imply less amplitude (quieter)but i think it means what i said.
this is called the doppler effect
greater than implies either a gain of frequency (true when it is travelling away), or a higher volume/amplitude, which is simply not true so B