This isnt really a homework question, just something to satisfy my curiosity but if it belongs in the homework section, I really apologize and if the mods could move it to that section, it would be much appreciated. Anywho, in class we talked about a particle accelerated by an electric field generated by capacitors. It then leaves through a hole and enters a constant magnetic field. That got me thinking, what if there is a constant magnetic field AND an electric field acting on the object at the same time? http://img442.imageshack.us/img442/406/physicsix5.png [Broken] Above is my interpretation of what would happen. Lets say a proton is released, it would travel toward the negative plate because it is accelerated in that direction because of the electric force. The motion of the proton in a magnetic field would generate a magnetic force and cause the proton to move in a circle. The net force on the object = magnetic force + electric force. My question is, how would the partice move? I know the manetic force and the electric force are components of the net force but can anyone help me understand the direction of movement? Since the particle does not have constant acceleration (so no constant velocity), is it possible to figure out the velocity of the particle? Here's what I think... F net = qvB + qE = ma; so v = (ma-qE)/qB but since the acceleration is changing constantly, would this be instantaneous velocity? If so, is the trajectory created by this velocity also changing constantly (since Fmag = mv^2/R)? Finally, what if gravity was involved? Now the net force has 3 components...but I cant imagine/figure out how the partice would move. The professor is out of town and will be for the next few days. I think that understanding this would really help me on the exam so any help would be greatly appreciated. Thanks!