A string tied between two post is oscillating at 3Hz. A student determines the standing waves have a length of 4 meters. What is the velocity of the wave?

12 m/s

Explanation:

Standing waves are waves that are formed between two fixed points in space, so they cannot propagate, but they are just oscillations about a fixed points. Examples of standing waves are the waves in a string.

The relationship between wavelength, frequency and speed of a wave is given by the wave equation:

where

v is the speed of the wave

f is its frequency

is its wavelength

For the standing wave in this problem we have:

f = 3 Hz is the frequency of the wave

is the wavelength

Solving for v, we find the velocity of the wave:

there are no contact forces mentioned on the list of choices that you've provided.