a. Lengthen the string. b. Decrease the tension. c. Make the string thicker (increasing the mass per unit length of the string).
Work Step by Step
a. For waves, the wave speed equals the frequency multiplied by wavelength. Increasing the wavelength by increasing the length (see Figure 21.5; increasing the distance between the endpoints increases the wavelengths) will decrease the frequency. b, c. A more advanced treatment of waves in strings shows that the wave speed decreases if the tension is decreased or if the mass per unit length of the string is increased (for example, by winding wire around the string). For waves, the wave speed equals the frequency multiplied by wavelength. Decreasing the wave speed while keeping wavelength the same means that the frequency/pitch is lowered, which was the goal.