Which of the following situations represents a positive displacement of a carton? Assume positive position is measured vertically upward along a y-axis. AA delivery person waiting for an elevator lowers a carton onto a dolly.
BWhen the elevator doors open, the delivery person lifts the dolly over the threshold of the elevator.
CThe delivery person pushes the dolly to the back of the elevator while pressing a floor button.
DThe door closes and the elevator moves from the 10th to the 4th floors.
Refer to the figure below to answer the following questions.

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