Why does a pendulum move from side to side?

Answer 1

A swinging Foucault Pendulum will change its direction 360° over a 24-hour period as Earth rotates on its axis. The motion of the pendulum is independent of Earth motions. The pendulum actually swings in the same direction it is Earth that rotates beneath the pendulum.

Answer 2

Pendulums move in accordance with Newton's laws of motion, and the force of gravity.

answ2. Pendulums are free to move in directions other than side to side. The balance wheel in a mechanical watch is an example of rotary oscillation.

Indeed one cannot limit the motion of a pendulum as "from side to side", for an ordinary mass hanging on a long string will precess throughout the day. [There used to be a marvellous one in the Smithsonian - a popular exhibit. Foucalt pendulum.].

And an interesting speculation is why does the mass disappear from the equation. As expressed in the 'l/g' expression, one might be led to believe a mass-less pendulum would resonate! The disappearance of mass in the math does not infer that a mass-less pendulum would work.

{For a demonstration of oscillation, we used to suspend a small mass on an elastic cord (a rubber band). This device has several different periods, depending on the particular oscillation.

a) The up-and-down oscillation demonstrates the principle of vibration isolation - (just vary the frequency of your oscillatory input);

b) an ordinary simple pendulum;

c) a pendulum where the mass describes a circle of rotation, with the string describing the surface of a cone;

d) and the 'watch-spring type of circular motion.

So with a single mass and a single spring, four different oscillations may be generated. [The trick is that the spring force is of a different nature in each case. And the centroid of mass alters also!]}

Answer 3

-- A moving object doesn't need any force to keep it moving.

-- The speed, or direction, or both, of a moving object is changed

by any force that's not cancelled by another equal opposite force.

Answer 4

Gravity. Another possible variable is wind resistance. Thanks. Lolz

Answer 5

weight and the tension in the string

Answer 6

gravitational energy

Answer 7

It keeps the earth movement.