In a simple harmonic motion, the maximum displacement from the equilibrium position is equal to the amplitude. Given that the amplitude is 20 cm, the maximum displacement is also 20 cm.
In one half of the period, the motion of the object starts from the extreme position (maximum or minimum displacement) and returns to the equilibrium position. Therefore, the maximum change in position in one half of the period is equal to twice the amplitude.
Maximum change in position = 2 * Amplitude Maximum change in position = 2 * 20 cm Maximum change in position = 40 cm
Hence, the maximum change in position in one half of the period is 40 cm.