PHY BK ANS 3B
3B Wave Motion II
5
Chapter 5
Nature of Waves
Practice 5.1 (p. 7)
1
B
2
D
3
(a) Transverse wave
11
Speed = f = 5 0.2 = 1 m s1
1 1
(ii) Period = = = 0.2 s f 5
(a) (i)
(b) A heavier string (length unchanged) has greater mass per unit length. Therefore,
(b) Longitudinal wave
4
(a) Water wave and EM wave
(b) Sound wave
5
12
For case I, energy is transferred to the cork directly from the stone. For case II, energy is transferred to the cork through water waves.
6
= 1.6667
= 1.67 m s1
(b) By v = f,
from what starts the wave, e.g. a stone.
Wavelength =
Practice 5.2 (p. 21)
1
C
2
C
3
A
4
D
5
C
6
C
7
B
8
(a) C
13
(c)
v 1.6667
=
= 0.833 m f 2
12
=4m
3
12
(b) Wave speed = = 6 m s1
2
(a) Wavelength =
(c)
By v = f, frequency =
v 6
= = 1.5 Hz λ 4
Practice 5.3 (p. 29)
(b) A
10
the wave speed decreases. distance travelled
(a) Wave speed = time taken
5
=
3
An object floating on water vibrates as a wave passes it. The energy of the object comes
9
Nature of Waves
B
4
= 0.16 m
25
distance travelled
(b) Speed = time taken
4
= = 0.4 m s1
10
v 0.4
(c) Frequency = =
= 2.5 Hz λ 0.16
1
B
2
A
3
(a) Wavelength = 20 cm λ 0.2
(b) Speed = f = =
= 2 m s1
T 0.1
4
(a) Amplitude = 50 cm
(a) Wavelength =
(b) Time taken = 2 2 = 4 s
5
From the graph, the period of the wave is 4 s.
By v = f, wavelength =
W and Y are momentarily at rest.
X is moving upwards.
v
= vT = 10 4 = 40 m f Z is moving downwards.
New Senior Secondary Physics at Work
1
Oxford University Press 2009
3B Wave Motion II
Chapter 5
(b) (i)
6
Nature of Waves
Particles X and Z are in phase.
(ii) Particles W and Y are in antiphase.
(iii) Particle W is on a wave crest at t = 0.6 s.
8
(a) (i)
Wavelength = 6.4 cm
(ii) Since particle P undergoes the
smallest number of oscillation at the instances shown, P should have
1
oscillated for period from t = 0
4
to t = 0.5 s.
Frequency =
0.25
= 0.5 Hz
0.5
(iii) Speed = f
= 0.5 0.064
= 0.032 m s1
5
Chapter 5
Nature of Waves
Practice 5.1 (p. 7)
1
B
2
D
3
(a) Transverse wave
11
Speed = f = 5 0.2 = 1 m s1
1 1
(ii) Period = = = 0.2 s f 5
(a) (i)
(b) A heavier string (length unchanged) has greater mass per unit length. Therefore,
(b) Longitudinal wave
4
(a) Water wave and EM wave
(b) Sound wave
5
12
For case I, energy is transferred to the cork directly from the stone. For case II, energy is transferred to the cork through water waves.
6
= 1.6667
= 1.67 m s1
(b) By v = f,
from what starts the wave, e.g. a stone.
Wavelength =
Practice 5.2 (p. 21)
1
C
2
C
3
A
4
D
5
C
6
C
7
B
8
(a) C
13
(c)
v 1.6667
=
= 0.833 m f 2
12
=4m
3
12
(b) Wave speed = = 6 m s1
2
(a) Wavelength =
(c)
By v = f, frequency =
v 6
= = 1.5 Hz λ 4
Practice 5.3 (p. 29)
(b) A
10
the wave speed decreases. distance travelled
(a) Wave speed = time taken
5
=
3
An object floating on water vibrates as a wave passes it. The energy of the object comes
9
Nature of Waves
B
4
= 0.16 m
25
distance travelled
(b) Speed = time taken
4
= = 0.4 m s1
10
v 0.4
(c) Frequency = =
= 2.5 Hz λ 0.16
1
B
2
A
3
(a) Wavelength = 20 cm λ 0.2
(b) Speed = f = =
= 2 m s1
T 0.1
4
(a) Amplitude = 50 cm
(a) Wavelength =
(b) Time taken = 2 2 = 4 s
5
From the graph, the period of the wave is 4 s.
By v = f, wavelength =
W and Y are momentarily at rest.
X is moving upwards.
v
= vT = 10 4 = 40 m f Z is moving downwards.
New Senior Secondary Physics at Work
1
Oxford University Press 2009
3B Wave Motion II
Chapter 5
(b) (i)
6
Nature of Waves
Particles X and Z are in phase.
(ii) Particles W and Y are in antiphase.
(iii) Particle W is on a wave crest at t = 0.6 s.
8
(a) (i)
Wavelength = 6.4 cm
(ii) Since particle P undergoes the
smallest number of oscillation at the instances shown, P should have
1
oscillated for period from t = 0
4
to t = 0.5 s.
Frequency =
0.25
= 0.5 Hz
0.5
(iii) Speed = f
= 0.5 0.064
= 0.032 m s1