# LOOPING THE LOOP!

A particle of mass $m=1\text{ kg}$ and charge $q=3\text{ C}$ is hung from a light inextensible string of length $l=2\text{ m}$. The entire system is placed in a uniform horizontal electric field of magnitude $8\text{ V/m}$. What must be the minimum initial horizontal velocity with which the particle must be projected so that it completes a vertical circle?

Details and Assumptions

• The gravitational acceleration is $g=-10\text{ m/s}^2$.
• The particle is initially at the lowest point.
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