Calculating Velocity from Kinetic Energy: Solving for v in the r=mv/qb Formula

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To calculate the radius of a proton's circular path in a magnetic field using the formula r=mv/qb, the velocity (v) must first be determined from the kinetic energy. The kinetic energy of the proton is given as 4.6×10−16 J, and the definition of kinetic energy is 1/2 mv^2. By rearranging the kinetic energy formula to solve for v, and knowing the mass of a proton, one can find the necessary velocity. Once v is calculated, it can be substituted back into the original formula to find the radius. This approach effectively links kinetic energy to the radius of motion in a magnetic field.
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A proton with a kinetic energy of 4.6×10−16 J moves perpendicular to a magnetic field of 0.26 T. What is the radius of its circular path?


I know the formula is r=mv/qb. the only thing not given is v. So my question is how do I get v from Joules? I know 1 Joule=1N/m, and that N=ma, but I don't know how to get velocity from that. Any help on that part would be greatly appreciated : )
 
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What's the definition of kinetic energy?
 
1/2 mv^2
 
baylorbelle said:
1/2 mv^2
There you go. Now you can solve for v using the given information. (You may have to look up the mass of a proton.)
 
thanks!
 
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