# Electric dipole's maximum angular velocity

1. ### superamazinPI

1
1. The problem statement, all variables and given/known data
Consider an electric dipole located in a region with an electric field of magnitude $$\vec{E}$$ pointing in the positive y direction. The positive and negative ends of the dipole have charges +q and -q, respectively, and the two charges are a distance D apart. The dipole has moment of inertia I about its center of mass. The dipole is released from angle $$\theta$$, and it is allowed to rotate freely.

What is $$\omega_{max}$$, the magnitude of the dipole's angular velocity when it is pointing along the y axis?

2. Relevant equations

dipole moment p= qd

$$\vec{\tau}$$=$$\vec{p}$$X$$\vec{E}$$

U= -$$\vec{p}$$ $$\cdot$$$$\vec{E}$$

3. The attempt at a solution

I attempted to use energy, but I am not sure how to do it correctly - does potential energy equal kinetic? is the potential energy the one described in the above equation?

2. ### mjsd

860
dipole in a E field gives torque, torque is a force and can then be related to moment of inertia and angular acceleration

3. ### clem

1,276
You can use your expression for U and (1/2)I\omega^2 for the KE.

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