1. Ātrums šķērsviļņa Uz 25 metru garas virves ir 50 m/s. Virves stiepes spēks ir 200 N. Nosakiet virves masu.
A. 0.08 kg
B. 0.5 kg
Aptuveni 0.8 kg
D. 2.0 kg
Zināms:
Length of rope (l) = 25 m
Speed of transverse wave (v) = 50 m/s
Tension force of rope (T) = 200 N
Vēlējās: Mass of rope (m)
šķīdums:
This problem can be solved using the formula of the wave propagation formula on the rope.
Pareizā atbilde ir D.
2. On the surface of the lake floats two pieces of wood, the distance between them is 6 m. The waves propagate on the surface of the lake. When the first wood has moved up and down three times, the second wood just moved up and down once. If every 2 seconds both kinds of wood move up and down three times, the wave propagation is …
A. 4.5 m/s
B. 3.0 m/s
Aptuveni 2.0 m/s
D. 1.5 m/s
Zināms:
Distance between both woods (l) = 6 meters
The first timber has moved up and down three times; the second wood just moved up and down once.
Frequency (f) = 3 / 2 = 1.5 hertz
Vēlējās: Speed of wave (v)
šķīdums:
When the first wood moves up and down once, the viļņa garums 1 travels to the second wood. When the first wood moves up and down twice, the wavelength 2 travels to the second wood. When the first wood moves up and down three times, the wavelength one has arrived at the second wood position, so that at the same time the second wood moves up and down once.
Tādējādi, attālums between the first wood and the second wood is two wavelengths (2 λ), as shown in the picture on the side.
Distance of 1 wavelength (λ) = 6 / 2 = 3 meters
The speed of the wave propagation (v):
v = f λ = (1.5 hertz)(3 meters)
v = 4.5 m/s
Pareizā atbilde ir A.
3. Factors that accelerate the propagation of waves on the strings are…
(1) extend the wire
(2) magnifying the wire mass
(3) increase the wire tension
(4) enlarge the wire size The correct statement is…
A. (1), (2), (3) and (4)
B. (1), (2), and (3)
C. (3) un (4)
D. (3) only
šķīdums:
The formula of the speed of the wave propagation on the strings:
Pareizā atbilde ir A.
v = speed of the wave propagation on the strings
T = tension force of strings
μ = density of the string
m = mass of the string
l = length of string
4. On a rope propagates a wavelength rope with a frequency of 50 Hz and a wavelength of 2 m. Period and velocity of the wave are…
A. 0.02 seconds and 50 ms-1
B. 0.02 seconds and 100 ms-1
C. 0.04 seconds and 50 ms-1
D. 0.5 seconds and 100 ms-1
Zināms:
Frequency (f) = 50 Hz
The wavelength (λ) = 2 meters
Vēlējās: Period (T) and speed of the wave (v)
šķīdums:
Period :
T = 1/f = 1/50 Hz = 0.02 seconds
Viļņa ātrums:
v = f λ = (50 1/second)(2 meters) = 100 meters/second
Pareizā atbilde ir B.
5. A cork on the surface of water moves up and down due to the surface water waves. The time required from a crest to next crest is 1.2 seconds. If on the water surface, the distance between two crests is 10 cm, then determine the speed of the wave propagation.
A. 12 ms-1
B. 12 cm s-1
Aptuveni 8,3 ms-1
D. 8,3 cm s-1
Zināms:
The time required from crest to the next crest = the time interval for one wavelength = period (T) = 1.2 seconds.
Distance between two crests = distance of 1 wavelength (λ) = 10 cm
Meklē: Speed of the wave propagation (V)
šķīdums:
Speed of the wave propagation :
v = f λ = λ / T = 10 cm / 1.2 seconds = 8.3 cm/second = 8.3 cm.s-1
Pareizā atbilde ir D.
