20.16. Set Up: For motion in an arc of a circle, and the net force is radially inward, toward the center of the circle. The direction of the force is shown in Figure 20.16. The mass of a proton is Figure 20.16 Solve: (a) is opposite to the right-hand rule direction, so the charge is negative. gives and (b) The magnetic force is much larger than the weight of the particle, so it is a very good approximation to neglect gravity. (c) The magnetic force is always perpendicular to the path and does no work. The particles move with constant speed. 20.17. Set Up: Solve: and Reflect: The radius of the circular path decreases when B increases. 20.18. Set Up: For motion in an arc of a circle, and the net force is radially inward, toward the center of the circle. The direction of the force is shown in Figure 20.18. Since the electron has negative charge, the force on it is opposite to the right-hand rule direction. The magnetic force does no work and the electron moves at constant speed. The distance from
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.