Igot the correct answer, but i don't know what i did. why is the answer e?

Explanation:

Displacement is the straight line distance from the starting position to the final position.

Person X walks halfway around circle.  So her displacement is 100 m.

Person Y walks 3/4 of the way around.  So his displacement is 50√2 m ≈ 70.7 m.

Person Z walks completely around the circle, so their displacement is 0 m.

Therefore:

Z < Y < X

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.