An ant is on the pendulum bob of a clock. What would be its displacement in one time period?

Answer: the displacement is 0

Explanation:

Displacement is defined as the difference between the final position and the initial position.

now, one time period is defined as the time that the pendulum needs to do a full cicle (so after one time period, the position of the pendulum returns to the same place) this means that the final position and the initial position is the same, then the displacement is 0.