Did the wave slow down as it bounced

• Did the wave slow down as it bounced back and forth along the spring?

Transverse vs. Longitudinal • Put your group’s definitions and diagrams on a whiteboard.

Definitions • Transverse wave – A particle in the medium will move perpendicular to the direction the wave is traveling as the pulse passes through it.

Definitions • Longitudinal wave – A particle in the medium will move parallel to the direction the wave is traveling as the pulse passes through it.

Conclusions from WS 1? • Wave races • The speed of a wave pulse is constant unless the tension or spring type is changed. – Amplitude, pulse width, and distance traveled do NOT affect wave speed. – The tighter the spring, the faster the wave moves.

Conclusions • Fixed vs. free end? • For a fixed end reflection, the wave “flips. ”

Conclusions • For a free end reflection, the wave doesn’t “flip. ”

What happens when two wave pulses collide?

• Interference – Two (or more) waves “collide, ” but pass through each other undamaged – Superposition Principle: when waves interfere with each other, the resulting wave is the sum of their amplitudes at each point. – What would it be like if superposition existed for objects?

Destructive Interference

Constructive Interference

Constructive Interference • crests aligned with crests • waves are “in phase”

Destructive Interference • crests aligned with troughs • waves are “out of phase”

• Interference – Combine the amplitudes of the waves • Above axis is positive, below is negative – The result is the superposition of the waves – Constructive wave gets bigger – Destructive wave gets smaller