14. A particle with mass m and positive charge q starts from rest at the origin under a uniform electric field in the +y-direction and a uniform magnetic field directed out of the page, so
. Neglecting gravity, the particle is accelerated by the E field, but the magnetic force bends it to the right and the resulting trajectory is shown in the figure. At point P, the particle reaches its maximum height ymax. What is the velocity of the particle at point P?
(A)
(B) 
(C) 
(D) 
(E) 
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統計: 尚無統計資料
統計: 尚無統計資料