1. 의 속도 횡파 25미터 길이의 줄에 50m/s의 속도가 걸려 있습니다. 줄의 장력은 200N입니다. 줄의 질량을 구하세요.
A. 0.08kg
나. 0.5kg
C. 0.8kg
D. 2.0kg
알려진 바에 따르면:
Length of rope (l) = 25 m
Speed of transverse wave (v) = 50 m/s
Tension force of rope (T) = 200 N
구함 : Mass of rope (m)
솔루션 :
This problem can be solved using the formula of the wave propagation formula on the rope.
정답은 D입니다.
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. 4.5m/s
B. 3.0m/s
C. 2.0 m/s
D. 1.5 m/s
알려진 바에 따르면:
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
구함 : Speed of wave (v)
솔루션 :
When the first wood moves up and down once, the 파장 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.
그래서 거리 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 = 4.5m/s
정답은 A입니다.
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), 및 (3)
C. (3) 및 (4)
D. (3) only
솔루션 :
The formula of the speed of the wave propagation on the strings:
정답은 A입니다.
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
알려진 바에 따르면:
주파수(f) = 50Hz
The wavelength (λ) = 2 meters
구함 : Period (T) and speed of the wave (v)
솔루션 :
Period :
T = 1/f = 1/50 Hz = 0.02 seconds
파동의 속도:
v = f λ = (50 1/second)(2 meters) = 100 meters/second
정답은 B입니다.
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. 12ms-1
B. 12 cm s-1
C. 8,3ms-1
D. 8,3 cm s-1
알려진 바에 따르면:
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
구함: Speed of the wave propagation (V)
솔루션 :
Speed of the wave propagation :
v = f λ = λ / T = 10 cm / 1.2 seconds = 8.3 cm/second = 8.3 cm.s-1
정답은 D입니다.
