Tut 3

1
Tut 3
1. Die vibrasie van n 600 Hz stemvurk
veroorsaak staande golwe in n snaar wat aan
beide kante vas is. Die golfspoed vir die snaar
is 400 m/s. Die staande golf het vier loops en
n amplitude van 2 mm. Wat is die lengte van die
snaar? Vibrations from a 600 Hz tuning fork sets
up standing waves in a string clamped at both
sides. The wave speed for the string is 400 m/s.
The standing wave has four loops and an
amplitude of 2 mm. What is the length of the
string? (3)
Bepaal die golf getal k van die
ossilasie. Determine the wave number of the
oscillation. (2)
Bepaal die hoek frekwensie van die
ossilasie. Determine the angular frequency of the
oscillation. (2)
2
Skryf n vergelyking neer vir die verplasing van
die snaar as n funksie van posisie en tyd. Write
an equation for the displacement of the string as
a function of position and time. (2)
2. Dit word geadverteer dat n hoë kwaliteit
luidspreker, by volle volume, frekwensies tussen
30 Hz en 18000 Hz met uniforme intensiteit van ?
3 dB kan voortbring. (oor hierdie frekwensie
gebied sal die intensiteitvlak met nie meer as
3 dB van die gemiddelde verskil). Met watter
faktor sal die intensiteit verander vir n
maksimum intensiteitvlak verandering van 3 dB? A
high quality loudspeaker is advertised to
reproduce, at full volume, frequencies from 30 Hz
to 18000 Hz with uniform intensity ? 3 dB.(over
this frequency range , the intensity level does
not vary by more than 3 dB) By what factor does
the the intensity change for the maximum
intensity level change of 3 dB? (4)
3
3. Ultra-klankgolwe word gebruik om die
vloeisnelheid van bloed te bepaal. Veronderstel
n toestel straal klank teen 500 kHz uit en dat
die snelheid van klank in die menslike liggaam
1540 m/s is. Wat is die frekwensie van die klank
wat die bloedselle bereik as bloed normaalweg
teen 2.0 cm/s in groot are beweeg direk na die
klank bron toe? Ultrasound waves are used to
measure blood flow speeds. Suppose a device emits
sound at 500 kHz, and the speed of sound in human
tissue is taken to be 1540 m/s. What is the
frequency of the sound that reaches the blood
cells if blood is normally flowing in large
arteries at 2.0 cm/s directly towards the sound
source? (3)
As die klank golwe nou van die bloedselle af
terug gereflekteer word, wat is die frekwensie
van die gereflekteerde klank golwe wat deur n
waarnemer by die aanvanklike bron waargeneem
word? If the sound waves is reflected from the
blood cells, what is the frequency of the
reflected sound waves detected by an observer
standing next to the original source? (3)
4
Wat is die frekwensie van die swewinge wat deur
die waarnemer gehoor sal word? What is the
frequency of the beats that such an observer will
hear? (2)
4. n Besondere orrelpyp kan resoneer by 264 Hz,
352 Hz en 440 Hz, maar nie by enige frekwensies
tussen in nie. Is dit n oop of toe pyp? A
particular organ pipe can resonate at 264 Hz, 352
Hz and 440 Hz, but not at any frequencies in
between. Is it an open or closed pipe? (3)
Wat is die fundamentele frekwensie? What is the
fundamental frequency? (1)
Watter harmonikas word gehoor? Which harmonics
are heard? (3)