A 65.25 kg person holding a steel ball stands motionless on a frozen lake. The person then throws the ball, which propels the person at 1.25 m/s to the
right and the ball 4.05 m/s to the left. If the initial momentum of the system is
zero, what is the mass of the steel ball?
A. 16.11 kg
B. 4.03 kg
C. 3.24 kg
D. 20.14 kg

It may seem strange that the selected velocity does not depend on either the mass or the charge of the particle. (for example, would the velocity of a neutral particle be selected by passage through this device? ) the explanation of this is that the mass and the charge control the resolution of the device--particles with the wrong velocity will be accelerated away from the straight line and will not pass through the exit slit. if the acceleration depends strongly on the velocity, then particles with just slightly wrong velocities will feel a substantial transverse acceleration and will not exit the selector. because the acc