Please go into detail with steps as to why you did what you did. ALSO put the eq
ID: 1591650 • Letter: P
Question
Please go into detail with steps as to why you did what you did. ALSO put the equation you used or are referring to. this will really help me. THANK YOU!
13)A fisherman fishing from a pier observes that the float on his line bobs up and down, taking 2.4 s to move from its highest point to its lowest point. He also estimates that the distance between adjacent wave crests is 48 m. What is the speed of the waves going past the pier?
A. 5 m/s
B. 10 m/s
C. 20 m/s
D. 120 m/s
14)If a wave speed of 362 m/s and a period of 4.17 ms, what is its wavelength?
A. 1510 m
B. 1.51 m
C. 86,800 m/s
D. 0.0115 m/s
15)sound waves produced in one end of a cardboard tube (point A) move to the ear of a listener at the other end of the tube (point B). As the waves move from A to B inside the tube, which of the following are true?
A. information (energy) is transferred from A to B
B. air molecules are transferred from A to B
C. oscillations of molecules occur perpendicular to a line from A to B
D. the frequency of oscillations decreases as the waves move farther in the tube from A to B
16)As a musician warms up a wind instrument to play, the temperature of the air in the instrument increases. what is the result of this change on the fundamental for the instrument and why?
A. an increase in frequency and wavelength
B. an increase in frequency and a decrease in wavelength
C. an increase in wave speed and frequency
D. an increase in wave speed and a decrease in frequency
17)A 0.09 kg wire that is 1.0 m long is under tension. when a transverse wave of frequency 890 Hz travels down the wire, its wavelength is 0.10 m and its amplitude is 6.5 mm. what is the tension in the wire?
A. 710 N
B. 820 N
C. 930 N
D. 1100 N
18)The air column in a tube open at one end and closed at the other end is 0.8 m long and produces a fundamental not of frequency 100 Hz when the tube is struck to set up a standing wave. what are the frequencies of the next two frequencies of this tube?
A. 200 and 300 Hz
B. 100 and 200 Hz
C. 200 and 400 Hz
D. 300 and 500 Hz
Explanation / Answer
13) adjacent wave crests=Lamda=48m
f=1/T
Since 1/2 T=2.4s
(It only moves from highest to lowest, NOT Highest-lowest-higest i.e. a full period, so its half the period. need to multiply the time by 2 to get the full period)
T=4.8s
v=f*Lamda
=(1/4.8)*48
=10m/s
14) f = c (speed of the wave in m/s)
= Wavelength in meters
f = frequency in Hz
if period is 4.17 ms, frequency is 1/T = 239.8=240 Hz (approx.)
= 362 m/s / 240 Hz = 1.51 meters
15) information (energy) is transferred from A to B and also the frequency of oscillations decreases as the waves move farther in the tube from A to B.
16) When you play a wind instrument it warms-up the air inside (because breath is warm). The speed of sound in air (v) increases as temperature increases.
v = f therefore f = v/. doesn't change much as it fixed by the dimensions of the instrument, so when v rises f rises and the instrument plays sharp.
17) v= lambda*f =sqrt(F/muo) where F= force or tension in wire and muo = Mass per unit length
F or T = lambda^2 * f^2 * M/L = 0.1^2 * 890 *2 *0.09/1.0 = 712.89 N = 710 N approx
18) fn = nV/4L for container open at one end
fundamental frequency =f0 = V/4L
100 = V/4*0.8
V= 100*4*0.8 = 320m/s
therefore, frequencies of the next two frequencies of this tube = 2V/4L and 3V/4L
2* 320/4*0.8 and 3 * 320/4*0.8
200 and 300 Hz