Double Pendulum - Physics Stack Exchange most recent 30 from physics.stackexchange.com 2019-09-21T11:00:28Z https://physics.stackexchange.com/feeds/question/54835 https://creativecommons.org/licenses/by-sa/4.0/rdf https://physics.stackexchange.com/q/54835 2 Double Pendulum user61835 https://physics.stackexchange.com/users/21288 2013-02-23T08:01:25Z 2013-02-24T19:02:00Z <p>The equations of motions for the <a href="http://en.wikipedia.org/wiki/Double_pendulum" rel="nofollow">double pendulum</a> is given by </p> <p>$$\dot{\theta_1} = \frac{6}{ml^2}\frac{2p_{\theta1} - 3\cos(\theta_1 - \theta_2)p_{\theta2}}{16 - 9\cos^2(\theta_1 - \theta_2)}$$ </p> <p>and similarly for the other pendulum. In respect to what does the change in angle for the first pendulum refer to? Is it with respect to time? So that $\dot{\theta_1} = \frac{d\theta}{dt}$? </p> https://physics.stackexchange.com/questions/54835/-/54837#54837 4 Answer by Rafael Reiter for Double Pendulum Rafael Reiter https://physics.stackexchange.com/users/19945 2013-02-23T09:15:40Z 2013-02-23T09:15:40Z <p>Yes. The point always refers to the derivative with respect to time.</p> https://physics.stackexchange.com/questions/54835/-/54980#54980 2 Answer by Dan for Double Pendulum Dan https://physics.stackexchange.com/users/3936 2013-02-24T19:01:17Z 2013-02-24T19:01:17Z <p>The dot over a function or variable <a href="http://en.wikipedia.org/wiki/Newton%27s_notation" rel="nofollow">Isaac Newton's notation</a> for a derivative; in physics it always means a derivative with respect to time.</p> <p>Variables with two or three dots, like $\ddot{\theta}$ and $\dddot{\theta}$, represent second and third time derivatives respectively.</p>