Conceptual questions on sound/waves

[chops369]

Homework Statement

1. A child is swinging in simple harmonic motion. Where in his swing is the velocity the greatest? (Top, bottom, mid-way on the way up, or mid-way on the way down.)

2. A buoy in the ocean is bobbing up and down repeatedly. Explain why this is or isn't an example of simple harmonic motion.

3. A piece of a glacier falls into the ocean creating a large wave. What type of wave is this and how do you know? (Transverse or longitudinal)

Homework Equations

N/A

The Attempt at a Solution

1. I think that the velocity is greatest mid-way on the way up, but I'm not too sure.
2. I think that the buoy in the ocean is an example of simple harmonic motion since its movement is repeated.
3. Well, I know it's a transverse wave, but I don't know how to explain why. I would imagine that it's transverse since it has a distinct crest and trough, and because longitudinal has to do with varied compression.

 

[LowlyPion]

1. The child is undergoing harmonic motion between the extremes of potential energy at the top and kinetic energy at the bottom of the swing. Where then is tangential velocity the greatest? If you were just looking at the vertical component of velocity, then where would it appear greatest?

2. What is the buoy doing? Following the surface of the water? Is the water experiencing harmonic motion?

3. Consider:
http://en.wikipedia.org/wiki/Transverse_wave

 

[nlightner]

1. You are correct, the velocity is greatest at the mid-way point on the way up in simple harmonic motion. This is because at this point, the restoring force is at its maximum, resulting in the highest velocity.

2. Yes, the buoy in the ocean is an example of simple harmonic motion. This is because its movement is repetitive and can be described by a sinusoidal function, which is a characteristic of simple harmonic motion.

3. The wave created by the falling glacier is a transverse wave. This can be determined by the direction of the wave's oscillations, which are perpendicular to the direction of energy transfer. In longitudinal waves, the oscillations are parallel to the direction of energy transfer. Additionally, transverse waves have distinct crests and troughs, as you mentioned, while longitudinal waves have areas of compression and rarefaction.