The radial force on the particle is given by the Lorentz force. They don't give you the velocity so you have to solve for it in terms of the radius and get them to cancel.
The electrical charge of an election is negative!
One electron<span> itself has a negative </span>charge<span> of 1.6021766208 × 10 </span>−19<span> coulomb.
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Message me if you have any further questions!
Each ball :
P = m * m/sec
P = 1.0 * 5
P = 5.0 kg.m/sec
in stationary :
P = 1.0 kg * 0.0
P = 0.0 kg.m/sec
hope this helps!