6. Two pulses in a spring are travelling in the same direction as shown in the diagram at the right. As they proceed toward the wall, the distance between them a) decreases b) increases c) remains the same d) insufficient data 7. A train of waves is moving along a string as shown below. What is the wavelength? a) 6.0 m b) 2.0 m c) 1.5 m d) 0.75 m 8. A wave generator in a ripple tank produces waves at a frequency of 1.5 Hz in the deep water end. The water depth changes from 1.2 cm to 0.4 cm along a straight edge. The incident waves travel 9.0 cm/s with an amplitude of 0.3 cm. If the incident wavelength is 6.0 cm, what is the frequency of the waves in the shallow end? (3 marks) 9. Bats emit ultrasonic sound to help them locate obstacles. The waves have a frequency of 5.5 x 10# Hz. If the waves travel at 360 m/s, what is their wavelength? (3 marks) 10. The velocity of sound waves in cold air is 320 m/s, and in warm air is 380 m/s. If the wavelength of the sound was 2.0 m in cold air, what would the wavelength be in warm air? 160 (2. 35757 ) ( 3 marks ) 11. Waves in a lake are 5.0 m in length and pass an anchored boat 1.25 s apart. The speed of the waves is a) 0.25 m/s b) 4.00 m/s c) 6.25 m/s d) impossible to calculate with the given information. 12. The distance between successive crests in a series of water waves is 5.0 m, and the crests travel 8.6 m in 5.0 s. What is the frequency of a block of wood bobbing up and down on the water? a) 0.34 Hz b) 0.68 Hz c) 2.9 Hz d) 8.6 Hz