In measuring time period of a pendulum, it is advised to measure the time between consecutive passage through the mean position in the same direction. This is said to result in better accuracy than measuring time between consecutive passage through an extreme position. Explain.
It is advised to measure the time between consecutive passage through the mean position in the same direction rather than from extreme points because in simple harmonic motion, the motion is fixed with respect to mean position. The extreme points slowly change after a small interval of time due to reasons like air friction. It may lead to inaccuracy of the time period is measured from extreme positions. Hence, it is important to take the measurement from mean position because it is fixed.