Unformatted text preview: ong the trajectory indicated by the arrow. What is the velocity v of the bullet when it just leaves the tube? The friction is negligible. Figure 4: Illustration for problem 4. Figure 3: Illustration for problem 3. +2Q a c OQ +q b l a 2 Q Q R a a A Physics 2326002: Solutions to problems of Exam 1 Date: September 18, 2003 1. If we add vectors of field contributions from the upper pair of charges, the resulting Eupper is directed along x axis and its magnitude from simple geometry is Eupper = (R2 ke qa .  Ra + a2 /2)3/2 (1) The contribution from the lower pair of charges is directed against x axis and its magnitude is ke qa Elower = . (2) (R2 + Ra + a2 /2)3/2 Correspondingly, the overall field E at point A is directed along x axis and its magnitude is the difference of (1) and (2): E = ke qa (R2 1 1  2 . 2 /2)3/2  Ra + a (R + Ra + a2 /2)3/2 (3) One can easily see that potential = 0 at poi...
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 Spring '08
 Ingor
 Charge, Electric charge, Positive charge

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