1) A motorcycle traveling 25.0 m/s approaches a stationary police car with its siren on. The motorcyclist hears a siren with a frequency of 830 Hz. What is the actual frequency of the police siren? Use 340 m/s for the speed of sound.

2) A wire that is 1.0 m long with a mass of 90 g is under tension. When a transverse wave travels on the wire, its wavelength is 0.20 m and its frequency is 500 Hz. What is the tension in the string?

3) A 60-W speaker is blasting loud music. What is the sound intensity level ( in decibels) when you are standing 1.5 meters from the speaker? The threshold of human hearing is 1.01012W/m2.

4) Suppose you want to set up a simple pendulum so that each swing to the left or right takes 2.00 s. How long should it be....

a) at a location where g = 9.80 m/s2?

b) on a planet where g is 5.00 times what it is on Earth?