Question
(a) Viewers of Star Trek hear of an antimatter drive on the Starship Enterprise. One possibility for such a futuristic energy source is to store antimatter charged particles in a vacuum chamber, circulating in a magnetic field, and then extract them as needed. Antimatter annihilates with normal matter, producing pure energy. What strength magnetic field is needed to hold antiprotons, moving at $5.00\times 10^{7}\textrm{ m/s}$ in a circular path 2.00 m in radius? Antiprotons have the same mass as protons but the opposite (negative) charge. (b) Is this field strength obtainable with today’s technology or is it a futuristic possibility?
1. $0.261\textrm{ T}$
2. Yes, this field is obtainable with today's technology. \$0.50\textrm{ T} is doable with permanent magnets, and more than 1 tesla is possible with electromagnets using superconducting wires.

# OpenStax College Physics for AP® Courses, Chapter 22, Problem 14 (Problems & Exercises)

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