# What is Lagrangian equation for spherical pendulum?

## What is Lagrangian equation for spherical pendulum?

Note that the Lagrangian is independent of the angular coordinate φ. It follows that sin2θ˙ϕ is a constant. As a result, we get the system of differential equations for the spherical pendulum: ¨θ=sinθcosθ,˙ϕ2−gℓsinθ,ddt(sin2θ˙ϕ)=0⟹¨ϕ=−2˙θ˙ϕcosθsinθ.

## How do you construct a pendulum sphere?

Consider a two-dimensional pendulum of length l with mass M at its end. It is easiest to use spherical coordinates centered at the pivot since the magnitude of the position vector is constant: | r| = √(lr) · (lr) = √l2(r· r) = l.

What is the equation of motion of simple pendulum?

By applying Newton’s secont law for rotational systems, the equation of motion for the pendulum may be obtained τ=Iα⇒−mgsinθL=mL2d2θdt2 τ = I α ⇒ − m g sin ⁡ θ L = m L 2 d 2 θ d t 2 and rearranged as d2θdt2+gLsinθ=0 d 2 θ d t 2 + g L sin ⁡ If the amplitude of angular displacement is small enough, so the small angle …

### How do you find the Lagrangian equation of motion?

The Lagrangian is L = T −V = m ˙y2/2−mgy, so eq. (6.22) gives ¨y = −g, which is simply the F = ma equation (divided through by m), as expected.

### What is Hamiltonian equation?

These are called Hamilton’s equations. If the constraints in the problem do not depend explicitly on time, then it may be shown that H = T + V, where T is the kinetic energy and V is the potential energy of the system—i.e., the Hamiltonian is equal to the total energy of the system.

How are simple pendulums related to Lagrangian mechanics?

Simple pendulum via Lagrangian mechanics by Frank Owen, 22 May 2014 © All rights reserved The equation of motion for a simple pendulum of length l, operating in a gravitational field is \ This equation can be obtained by applying Newton’s Second Law (N2L) to the pendulum and then writing the equilibrium equation.

## How are Lagrange’s and Hamilton’s equations determined?

LAGRANGE’S AND HAMILTON’S EQUATIONS 2.1 Lagrangian for unconstrained systems For a collection of particles with conservative forces described by a potential, we have in inertial cartesian coordinates m¨x i=F i: The left hand side of this equation is determined by the kinetic energy func- tion as the time derivative of the momentump [email protected][email protected]_

## How is the equation of motion of a pendulum obtained?

This equation can be obtained by applying Newton’s Second Law (N2L) to the pendulum and then writing the equilibrium equation. It is instructive to work out this equation of motion also using Lagrangian mechanics to see how the procedure is applied and that the result obtained is the same.

How to calculate the energies of a spherical pendulum?

The free variables are θ and φ of spherical coordinates and the energies are given by θ ϕ ˙ 2). θ ϕ ˙ 2). θ ϕ ˙, p θ = ∂ H ∂ θ ˙ = ∂ K ∂ θ ˙ = m ℓ 2 θ ˙. θ. Note that the Lagrangian is independent of the angular coordinate φ. It follows that sin 2 θ ϕ ˙ is a constant.