# Cycloid pendulum (Huygens)

1. Mar 21, 2014

### alejandrito29

"Huygens' ingenious idea, which he put into practice, was to vary the eective length of the pendulum by allowing its cord to wrap partially around an obstruction as it swings"

the coordinates of cycloid are:

$$x=a(\theta -\sin \theta)$$
$$y=a(\cos \theta +1)$$

why in somes articles, they use the coordinates x,y for calculate de Lagrangian ???, when the unknown quantity is the period. My question is because, the coordinates of mass of pendulum not are x and y (this are the coordinates of cycloid).

for example in this links use x and y.

#### Attached Files:

• ###### cicloide.png
File size:
4.9 KB
Views:
168
2. Mar 23, 2014