A projectile is fired straight upward at 143 m/s.
How fast is it moving at the instant it
reaches the top of its trajectory?
Answer in units of m/s.

2) How fast is it moving at the instant it reaches
the top of its trajectory if the projectile is
fired upward at 12◦
from the horizontal?
Answer in units of m/s.

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