Answer: E. 2A
Explanation:
Amplitude(A) of a wave is the displacement of a body from its position of rest. The maximum value of the amplitude is the crest and the minimum value is the trough.
For a wave to make a cycle, it has to move to and from from its point of displacement.
If the red spot on the string completes a cycle, this means it must have pass through the crest and the trough making it 2 amplitudes.
Answer:
Solar conjunction is the period when Earth and Mars, in their eternal march around the Sun, are obscured from each other by the fiery orb of the Sun itself. Like dancers on either side of a huge bonfire, the two planets are temporarily invisible to each other
The average speed is the distance per time ratio. velocity is the rate at which the position changes