Pendulum suspended from Horizontal rotating hoop

In summary, the conversation discussed finding the Lagrangian of a system consisting of a massless hoop suspended horizontally and a simple pendulum attached to its edge. The Lagrangian was determined to be L = (1/2M[(L*d∅/dt)^2+(R+Lsin∅)^2*ω^2)+MgLcos∅, taking into account the kinetic and potential energies of the hoop and pendulum.
  • #1
Sswift
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Homework Statement


A massless hoop is suspended horizontally and is free to rotate about a vertical axis through its center with a constant angular velocity (omega). Attached to the edge of the hoop is a simple pendulum that is restricted to oscillate in only the radial direction. find the Lagrangian of the system.

M= mass of pendulum
L= Length of Pendulum
∅= angle the pendulum makes with the vertical
ω=angular velocity of hoop
R= radius of hoop

Homework Equations



L= T-U
T= Kinetic energy
U=Potential Energy


The Attempt at a Solution


T(hoop)=(1/2) I(hoop)*ω^2
But I is dependent upon the mass of the hoop and since the mass of the hoop is 0 so is I(hoop)->T(hoop)=0

T(pendulum)=(1/2)M[L*(d∅/dt)]^2+(1/2)I(pendulum)*ω^2
T=1/2M[(L*d∅/dt)^2+(R+Lsin∅)^2*ω^2
U=-MgLcos∅

L=(1/2M[(L*d∅/dt)^2+(R+Lsin∅)^2*ω^2)+MgLcos∅

Is this right?
 
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  • #2
Looks right to me.
 

1. What is a pendulum suspended from a horizontal rotating hoop?

A pendulum suspended from a horizontal rotating hoop is a physical system in which a pendulum (a weight attached to a string or rod) is attached to a hoop that is rotating horizontally. This creates a complex motion in which the pendulum swings back and forth and also rotates around the hoop.

2. What causes a pendulum suspended from a horizontal rotating hoop to move?

The motion of a pendulum suspended from a horizontal rotating hoop is caused by a combination of gravity, centripetal force from the rotating hoop, and inertia of the pendulum. As the hoop rotates, the centripetal force pulls the pendulum towards the center, while gravity pulls it downwards. This creates a circular motion in which the pendulum swings back and forth.

3. How does the length of the pendulum affect its motion in a pendulum suspended from a horizontal rotating hoop?

The length of the pendulum affects its motion in a pendulum suspended from a horizontal rotating hoop in a similar way to a regular pendulum. A longer pendulum will have a longer period (the time it takes for one full swing) and a shorter pendulum will have a shorter period. In this system, the length of the pendulum also affects the angle at which it swings around the hoop.

4. Can a pendulum suspended from a horizontal rotating hoop exhibit chaotic motion?

Yes, a pendulum suspended from a horizontal rotating hoop can exhibit chaotic motion. This means that the motion of the pendulum is unpredictable and highly sensitive to initial conditions. Small changes in the initial conditions, such as the angle or speed of the hoop, can result in significantly different outcomes.

5. What are the real-world applications of a pendulum suspended from a horizontal rotating hoop?

A pendulum suspended from a horizontal rotating hoop has practical applications in areas such as mechanical engineering, physics research, and education. It can be used to demonstrate complex motion and concepts such as centripetal force and chaotic systems. It can also be used in certain types of pendulum clocks and gyroscopes.

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