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models:basic_models:pendulum [2018/05/15 06:51]
jakobadmin [Intuitive]
models:basic_models:pendulum [2020/04/02 15:37] (current)
75.97.173.144
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 <tabbox Concrete> ​ <tabbox Concrete> ​
 {{ :​models:​pendulum.png?​nolink&​300|}} {{ :​models:​pendulum.png?​nolink&​300|}}
-[[models:​basic_models:​harmonic_oscillator]]+
 A normal pendulum hangs freely in a uniform gravitational field of strength $g$ on a rod with length $l$. The excitation above the ground state is measured by the angle $\phi$. At the end of the pendulum, we have a bob of mass $m$. This is shown in the picture on the right-hand side.  ​ A normal pendulum hangs freely in a uniform gravitational field of strength $g$ on a rod with length $l$. The excitation above the ground state is measured by the angle $\phi$. At the end of the pendulum, we have a bob of mass $m$. This is shown in the picture on the right-hand side.  ​
  
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 The [[formalisms:​lagrangian_formalism|Lagrangian]] of the pendulum is therefore The [[formalisms:​lagrangian_formalism|Lagrangian]] of the pendulum is therefore
  
-$$ L = T-V= \frac{1}{2} ml^2\dot{\phi}^2 - mgl (1-cos \phi), $$ +$$ L = T-U= \frac{1}{2} ml^2\dot{\theta}^2 - mgl (1-cos \theta), $$ 
-where $\dot{\phi}\equiv d\phi /dt $ denotes the time derivative. ​+where $\dot{\theta}\equiv d\theta /dt $ denotes the time derivative. ​
  
 Using the Euler-Lagrange equation we can derive the corresponding __equation of motion__ Using the Euler-Lagrange equation we can derive the corresponding __equation of motion__
models/basic_models/pendulum.1526359905.txt.gz · Last modified: 2018/05/15 04:51 (external edit)