A long, flexible string is stretched horizontally between two rigid supports. One end is fixed to a wall, and the other end passes over a frictionless pulley that holds a hanging mass. A student investigates how changes to the hanging mass affect the motion of small transverse pulses sent down the string.
(a) The student replaces the original hanging mass of 0.50 kg with a mass of 1.00 kg while keeping every other condition unchanged. Describe qualitatively how the change in hanging mass will affect the speed with which a small pulse travels from one support to the other. In your description, refer explicitly to properties of the string that determine pulse speed.
(b) During the experiment the student observes that when a pulse reaches the opposite end of the string, the string itself remains in place—only the disturbance has moved. Explain how the pulse transfers energy along the string without transferring mass.
(c) The student suggests that increasing the amplitude of the pulse (while keeping the hanging mass fixed) will make the pulse travel faster. Provide a reasoned argument supporting or refuting this claim for small-amplitude disturbances on the string, explicitly referencing relevant physical principles.