1. Relative to the Source:
* Moving Away from the Source: If the source is stationary and the pulse is traveling outwards, we say the pulse is propagating away from the source.
* Moving Towards the Source: If the source is stationary and the pulse is traveling back towards it, we say the pulse is reflecting back towards the source.
* Moving with the Source: If the source is moving, the pulse's motion relative to the source depends on the direction of motion of the source. If the source moves in the same direction as the pulse, the pulse appears to travel faster relative to the source. If the source moves in the opposite direction, the pulse appears to travel slower. This is known as the Doppler effect.
2. In terms of Wave Properties:
* Speed: The speed of the pulse describes how fast it travels through the medium. The speed is dependent on the properties of the medium (e.g., tension in a string, stiffness of a spring).
* Direction: The direction of the pulse describes the path it takes as it moves through the medium.
* Amplitude: The amplitude of the pulse describes the maximum displacement of the medium from its equilibrium position.
Example:
Imagine a rope tied to a wall. You give the rope a quick flick, creating a pulse that travels down the rope towards the wall. This pulse is moving away from the source (your hand) and will eventually reflect back towards you. The speed of the pulse is determined by the tension in the rope. The direction of the pulse is along the rope, and the amplitude is determined by the force of your flick.
Important Note: It's crucial to understand that the pulse itself is not a physical object that moves. Instead, it's a disturbance that propagates through a medium. The individual particles of the medium oscillate around their equilibrium positions, transferring the energy of the disturbance.
