When you sit in a chair, your body exerts a downward force on the chair. What is the reaction force?
A. The floor pushes up on the chair.
B. The chair pushes down on the floor.
C. Earth's gravity pulls up on the chain
D. The chair pushes up on your body.

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