1) Dagol and Smagol are fishing in a large river. Dagol observes that the float on his line bobs up and down, taking 2.50 s to move from its highest to its lowest point. Smagol estimates that the distance between adjacent wave crests is 46.3 m. What is the speed (in m/s) of the waves that they observe?

2) An earthquake generates two kinds of sound waves: a primary or P wave and a secondary or S wave.

An earthquake occurs and generates a P wave with speed 8.13 km/s and S wave with speed 4.29 km/s which reach a seismograph, located some distance away. If the P wave is detected 75.0 s before the S wave, how far away (in km) is the seismograph from the earthquake?

3) Uncle Ben, in his motor boat, is moving at 8.81 m/s in the direction in which the waves in the harbour are moving. Each time he passes over a crest, he feels a bump. The bumping frequency is 1.13 Hz, and the crests are separated by 5.21 m. What is the wave speed in m/s?

Hint: this problem is tricky! You'll need to remember relative velocity.

4) A transverse wave is travelling on a string with mass 5.23 g which is under tension 200 N. If the wave has frequency 244 Hz and wavelength 0.527 m, find the length of the string (in m).

5) Two copper wires are stretched under the same tension. Wire 1 has diameter 0.570 mm and waves travel along this wire with speed 51.6 m/s. Wire 2 has diameter 0.937 mm. Find the speed (in m/s) at which waves will travel along wire 2.

The density of copper is 8960 kg/m^3.

6) Carla is listening to music on a bluetooth speaker. Carla is (5.81x10^0) m away from the speaker and the intensity of sound where Carla is standing is (4.910x10^-10) W/m². Find the power (in watts) of sound emitted from the speaker.

7) Loretta increases the intensity of a sound source by a factor of 3.06. By how much (in dB) did the sound intensity level change?

8) A siren emits sound with intensity 0.776 W/m². What is the sound intensity level (in dB) of 5 identical sirens emitting sound all at the same time?

9) The sound intensity level of a lawn mower at a distance of 1.13 m is 100 dB. One morning, Woody wakes up to four of his neighbours mowing their lawns at a distance of 24.1 m from his open window. What is the sound intensity level (in dB) that Woody hears?

10) The sound intensity level of 15 karaoke singers in a bar is 112 dB. What is the intensity level of a single karaoke singer (assuming they all sing with the same power)?

11) Frasier is giving a speech and the power of his sound is 3.63 mW. What is the sound intensity level 6.63 m away from Frasier?

12) When one person cheers for the baseball player Sam 'Mayday' Malone, the sound intensity level at the pitching mound in the centre of the field is 62.1 dB. When the stadium full of fans cheer, the sound intensity level is 110 dB. How many fans are in the stadium?

Assume that every fan generates the same sound intensity at the centre of the field.