Two Harmonic Waves Are Described By $$y _ { 1 } = ( 3 \mathrm {~cm} ) \sin \left( \frac { 8.0 } { \mathrm {~m} } x + \frac { 2.0 } { \mathrm {~s} } t \right)$$

Multiple Choice

Two harmonic waves are described by $$y _ { 1 } = ( 3 \mathrm {~cm} ) \sin \left( \frac { 8.0 } { \mathrm {~m} } x + \frac { 2.0 } { \mathrm {~s} } t \right)$$ $$y _ { 2 } = ( 3 \mathrm {~cm} ) \sin \left( \frac { 8.0 } { m } x - \frac { 2.0 } { \mathrm {~s} } t \right)$$ What is the magnitude of the speed (in m/s) of the two traveling waves?

A) 16
B) 4.0
C) 8.0
D) 0.25
E) 2.0