Final answer:
To find the amplitude on a graph, measure the vertical distance from the midpoint of the wave to either its peak or trough; this measurement is the amplitude.
Step-by-step explanation:
To find the amplitude on a graph, you need to identify the highest or lowest point of the wave, also known as the peak or trough. The magnitude of the amplitude is the distance from the midpoint of the wave to its peak or to its trough (whichever you measure), vertically on the y-axis. In the given example, if the distance (marked by a green arrow in the figure) from the midpoint to the peak is 6.00 cm, then the amplitude is 6.00 cm. Here's how you could do it step by step:
Identify the midpoint of the wave, which is usually where the wave crosses the horizontal axis if it's centered.
Measure the vertical distance from this midpoint to the highest point of the wave (peak) or to the lowest point of the wave (trough).
The measured value is the amplitude of the wave.
In physics, particularly when discussing waves and harmonic motion, the amplitude can correspond to other values like voltage levels in electrical signals, represented as 'V/m' in some texts.