Question on speed, force, time?

Question

A pendulum is swinging...now as time elapses from it's initial release, the strides taken by the pendulum decrease in length...is speed effected...or is time between the force of the release and the swinging only a factor w/ the length of the stride of the swinging pendulum?

Thank you.

Answer 1

The top speed the pendulum reaches in a swing cycle must depend on how long the force of gravity has provided an acceleration to the pendulum. The longer the pendulum is subject to the acceleration the higher the speed of the pendulum.

Gravity acts vertically so the key thing in determining the effect of gravity on the pendulum is the pendulum's vertical displacement from it's high point in the swing to the point where the tension in the pendulum string stops gravity accelerating the pendulum any further (the point as it crosses the vertical).

The shorter that vertical displacement the less time for gravity to accelerate the pendulum.

As the stride of the pendulum decreases progressively the vertical displacement of the pendulum decreases so the acceleration provided by gravity acts over a shorter time period. This means that the pendulum has progressively less time under the influence of gravity to gather speed.

So speed is being effected. The pendulum is slowing down as the stride length of the pendulum decreases.

I could be wrong!

Answer 2

The force due to the mass of the pendulum is m*g and it is always acting downwards.This force offers resistance to the movement there by reducing the swing cycle and hence speed of the pendilum. Since the time is directly related to the length the decrease in one would decrease the other.

Answer 3

Hi. The pendulum is moving slower as the arc length decreases but the time it takes to swing back and forth is the same. Friction is one of the culprits.

Answer 4

The speed reached by the pendulum at the bottom of its arc is determined by how high it was when you released it. It's falling, just as it would if it weren't attached to anything. As it goes back up, it slows down to zero speed, and if it were an ideal pendulum, it would reach the exact same height as that from which it was released.

But it's not perfect, so it loses energy to heat (because of friction, mostly), so it does not reach the same height, so it does not reach the same speed at the bottom of its arc.

Answer 5

Speed is affected and in this specific senario it is affected by....... Gravity. You could make the arguement that it is also affected by wind resistance, but it is for the sake of arguing this point, affected by gravity.