Obviously, it will stop after sometime , after swinging. It is because we cannot apply energy continuously to the swinging pendulum.
The period of a swinging pendulum (or any other periodic system, for that matter) is the amount of time it takes to complete an entire cycle - meaning, the time it takes to start and then come back to the original position. For example, imagine a pendulum that is held so the string holding the mass is parallel to the ground. When you let go, it will swing all the way to the other side, and then all the way back to the starting position. The time it takes to get back to the starting position is the period.
The period of the pendulum can be influenced by the local magnitude of gravity, by the length of the string, and by the density of the material in the swinging rod (which influences the effective length).It's not affected by the weight of the bob, or by how far you pull it to the side before you let it go.
The force of gravity can be demonstrated by dropping an object from a height and observing it fall to the ground. Alternatively, one can use a pendulum to show the constant pull of gravity acting on the swinging object.
You know how when you pull a pendulum to the side and let it go, and then it swings away from you to the other side, but then it stops and turns around and swings back to you ? The period of the pendulum is the length of time it takes, after you let it go, to go away from you and then come back to your hand.
Gravity
You would...let me guess......EXPLODE?
Friction in the air. The pendulum actually swings across small air particles and slows it down. That's why, if you have a bowling ball attached to a string and you hold it up to your face and let go, it will swing back at you - but it is impossible for it to gain enough momentum that you had initially to hit you in the face! Common physics :)
To effectively use a crystal pendulum for divination and guidance, start by holding the pendulum in your dominant hand and asking clear yes or no questions. Focus on your intention and let the pendulum swing freely to indicate the answer. Practice regularly to strengthen your connection with the pendulum and trust your intuition.
Refugees would eventually die of starvation.
No. The pendulum will slow down by drag from air molecules until the motion becomes exactly the same as random motion caused by the air molecules. But I know what you are looking for-- "Isn't there some tiny detectable motion, even if you can't see it?" Let's look at a hanging pendulum that has NEVER been swung. If we tape a tiny mirror to it and bounce a laser beam off it, we will see a spot on the wall that vibrates from thermal (and ignoring environmental) noise. The average motion will NOT be zero in any finite time. BUT the average motion of the pendulum caused by noise will ALWAYS have some positive value depending on temperature (well, okay...zero at absolute zero). When the original swinging pendulum's motion equals the motion caused by random thermal noise, then the motion is ZERO. So it's a much better question than you might have thought! Quantum Mechanically the problem is even more interesting, since there is a small but finite possibility that the pendulum will launch itself into orbit without warning, but it all depends on statistics.
They would protest
The period of a pendulum ... or of anything that keeps doing the same thing over and over ... is the length of time it takes to finish one complete cycle. Pull a pendulum to the side and let it go. It returns to your hand after one period.